Organic materials able to detect analytes

ABSTRACT

The present invention generally relates to polymers with lasing characteristics that allow the polymers to be useful in detecting analytes. In one aspect, the polymer, upon an interaction with an analyte, may exhibit a change in a lasing characteristic that can be determined in some fashion. For example, interaction of an analyte with the polymer may affect the ability of the polymer to reach an excited state that allows stimulated emission of photons to occur, which may be determined, thereby determining the analyte. In another aspect, the polymer, upon interaction with an analyte, may exhibit a change in stimulated emission that is at least 10 times greater with respect to a change in the spontaneous emission of the polymer upon interaction with the analyte. The polymer may be a conjugated polymer in some cases. In one set of embodiments, the polymer includes one or more hydrocarbon side chains, which may be parallel to the polymer backbone in some instances. In another set of embodiments, the polymer may include one or more pendant aromatic rings. In yet another set of embodiments, the polymer may be substantially encapsulated in a hydrocarbon. In still another set of embodiments, the polymer may be substantially resistant to photobleaching. In certain aspects, the polymer may be useful in the detection of explosive agents, such as 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT).

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/005,631, filed Dec. 6, 2004, entitled “Organic Materials Able ToDetect Analytes,” by Rose et al., which claims priority under 35 U.S.C.§119(e) to U.S. Provisional Patent Application Ser. No. 60/527,395,filed Dec. 5, 2003, entitled “Organic Materials Able To DetectAnalytes,” by Rose, et al, both of which applications are incorporatedherein by reference in their entirety.

FEDERALLY SPONSORED RESEARCH

This invention was made with government support under Contract Number6891253, awarded by DARPA, and Grant No NAS2-02056, awarded by NASA. Thegovernment has certain rights in the invention.

FIELD OF INVENTION

The present invention generally relates to polymers with lasingcharacteristics and, in particular, to polymers with lasingcharacteristics that allow the polymers to be useful in detectinganalytes. In some cases, the polymers may be thermally, photochemically,and/or chemically stable in thin films. In certain instances, thepolymers may be soluble in organic solvents. In one set of embodiments,the polymers comprise conjugated backbones and use electron withdrawinggroups to affect the electron affinity of the polymers.

BACKGROUND

Semiconducting organic polymers have emerged as important class ofluminescent sensor materials due to their ability to self-amplify.Non-limiting examples of organic polymers that may be semiconductive aredisclosed in the following: U.S. patent application Ser. No. 09/305,379,filed May 5, 1999, entitled “Emissive Polymers and Devices IncorporatingThese Polymers,” by Swager, et al.; U.S. patent application Ser. No.09/935,060, filed Aug. 21, 2001, entitled “Polymers with High InternalFree Volume,” by Swager, et al.; and U.S. patent application Ser. No.10/680,714, filed Oct. 27, 2003, entitled “Emissive Sensors and DevicesIncorporating These Sensors,” by Swager, et al. Each of these isincorporated herein by reference.

SUMMARY OF THE INVENTION

The present invention generally relates to polymers with lasingcharacteristics that allow the polymers to be useful in detectinganalytes. The subject matter of the present invention involves, in somecases, interrelated products, alternative solutions to a particularproblem, and/or a plurality of different uses of one or more systemsand/or articles.

One aspect of the invention provides a device. In one set ofembodiments, the device is a device for detecting an analyte. In oneembodiment, the device includes a polymer that, upon interaction with ananalyte, exhibits a change in a lasing characteristic. The device alsoincludes, in some cases, an energy source able to cause the polymer tolase.

In another aspect, of the invention, an article is provided. Accordingto one set of embodiments, the article includes a polymer, that, uponinteraction with an analyte, exhibits a change in a stimulated emissionsignal that is at least 10 times greater than a change in a spontaneousemission signal of the polymer. In another set of embodiments, thearticle includes a polymer that, upon interaction with an analyte,exhibits a change in a lasing characteristic. In some cases, the polymerfurther includes a binding site for an analyte which, when it binds atthe site, changes the lasing characteristic.

The invention, in yet another aspect, provides a method. The method,according to one set of embodiments, is a method of determining ananalyte. The method, in one embodiment, includes acts of contacting apolymer with a sample suspected of containing an analyte, anddetermining a change in a lasing characteristic of the polymerindicative of the presence of the analyte in the sample. In anotherembodiment, the method includes acts of contacting a polymer with asample suspected of containing an analyte, and determining a change in astimulated emission signal of the polymer that is at least 10 timesgreater than a change in a spontaneous emission signal of the polymerindicative of the presence of the analyte in the sample.

In one set of embodiments, the polymer is fluorescent. The polymer mayalso be semiconductive in some cases. In one embodiment, the polymercomprises a conjugated backbone and one or more electron donating and/orelectron withdrawing groups bonded to or otherwise associated with thepolymer. For example, electron withdrawing groups may be bonded directlyto the conjugated backbone, or bonded to the polymer, but not bondeddirectly to the conjugated backbone.

In another aspect, the present invention is directed to a method ofmaking one or more of the embodiments described herein. In yet anotheraspect, the present invention is directed to a method of using one ormore of the embodiments described herein. In still another aspect, thepresent invention is directed to a method of promoting one or more ofthe embodiments described herein.

Other advantages and novel features of the present invention will becomeapparent from the following detailed description of various non-limitingembodiments of the invention when considered in conjunction with theaccompanying figures. In cases where the present specification and adocument incorporated by reference include conflicting and/orinconsistent disclosure, the present specification shall control. If twoor more documents incorporated by reference include conflicting and/orinconsistent disclosure with respect to each other, then the later-filedapplication shall control.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present invention will be described byway of example with reference to the accompanying figures, which areschematic and are not intended to be drawn to scale. In the figures,each identical or nearly identical component illustrated is typicallyrepresented by a single numeral. For the purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment of the invention shown where illustration is not necessary toallow those of ordinary skill in the art to understand the invention. Inthe figures:

FIG. 1 is a schematic diagram of a fluorescence quenching mechanism;

FIG. 2 is a chemical structure of a polymer of an embodiment of theinvention;

FIGS. 3A-3C are schematic diagrams of various planar lasing structures,in accordance with various embodiments of the invention;

FIG. 4 is a plot of emission intensity vs. input power, according to oneembodiment of the invention;

FIGS. 5A-5B are plots of spectral responses of certain embodiments ofthe invention;

FIG. 6 is a spectral response plot of another embodiment of theinvention;

FIG. 7 is a spectral response plot of yet another embodiment of theinvention;

FIG. 8 is a schematic diagram of energy levels in an example of aconjugated polymer of the invention;

FIG. 9 is a schematic diagram showing laser power output vs. pumpingpower input, in accordance with an embodiment of the invention;

FIG. 10 is a plot of emission intensity vs. input power, in anotherembodiment of the invention;

FIG. 11 is a schematic diagram showing excitation of a polymer of oneembodiment of the invention;

FIG. 12 is a schematic diagram of a detection system of an embodiment ofthe invention;

FIG. 13 is a schematic diagram of a detection system of anotherembodiment of the invention;

FIG. 14 is a schematic diagram of a charge transfer process in oneembodiment of the invention;

FIGS. 15A-15G illustrate various perfluorinated alkyl PPVs potentiallysuitable for use in certain embodiments of the invention;

FIGS. 16A-16B illustrate the preparation of certain polymers potentiallysuitable for use in some embodiments of the invention;

FIGS. 17A-17D illustrate various Stern-Volmer plots of certain polymersof the invention;

FIGS. 18A-18B illustrate various emission spectra of certain polymers ofthe invention;

FIGS. 19A-19N illustrate certain reaction pathways useful for preparingcertain polymers of the present invention;

FIGS. 20A-20D illustrate the analysis of trifluoromethyl substituted PPVand MEH-PPV, according to one embodiment of the invention;

FIGS. 21A-21B illustrate certain reaction pathways potentially suitablefor use in the present invention; and

FIGS. 22A-22D illustrate certain results from indole quenchingexperiments on PPEs with perfluorinated alkyls bonded directly to aconjugated backbone, according to one embodiment of the invention.

DETAILED DESCRIPTION

The present invention generally relates to polymers with lasingcharacteristics that allow the polymers to be useful in detectinganalytes. In one aspect, the polymer, upon an interaction with ananalyte, may exhibit a change in a lasing characteristic that can bedetermined in some fashion. For example, interaction of an analyte withthe polymer may affect the ability of the polymer to reach an excitedstate that allows stimulated emission of photons to occur, which may bedetermined, thereby determining the analyte. In another aspect, thepolymer, upon interaction with an analyte, may exhibit a change instimulated emission that is at least 10 times greater with respect to achange in the spontaneous emission of the polymer upon interaction withthe analyte. The polymer may be a conjugated polymer in some cases. Inone set of embodiments, the polymer includes one or more hydrocarbonside chains, which may be parallel to the polymer backbone in someinstances. In another set of embodiments, the polymer may include one ormore pendant aromatic rings. In yet another set of embodiments, thepolymer may be substantially encapsulated in a hydrocarbon. In stillanother set of embodiments, the polymer may be substantially resistantto photobleaching. In certain aspects, the polymer may be useful in thedetection of explosive agents, such as 2,4,6-trinitrotoluene (TNT) and2,4-dinitrotoluene (DNT).

The following documents are incorporated herein by reference: U.S.patent application Ser. No. 09/305,379, filed May 5, 1999, entitled“Emissive Polymers and Devices Incorporating These Polymers,” by Swager,et al.; U.S. patent application Ser. No. 09/935,060, filed Aug. 21,2001, entitled “Polymers with High Internal Free Volume,” by Swager, etal., now U.S. Pat. No. 6,783,814, issued Aug. 31, 2004; U.S. patentapplication Ser. No. 10/324,064, filed Dec. 18, 2002, entitled “EmissivePolymers and Devices Incorporating These Polymers,” by Swager, et al.,published as 2003-0178607 on Sep. 25, 2003; U.S. patent application Ser.No. 10/680,714, filed Oct. 27, 2003, entitled “Emissive Sensors andDevices Incorporating These Sensors,” by Swager, et al.; U.S.Provisional Patent Application Ser. No. 60/527,395, filed Dec. 5, 2003,entitled “Organic Materials Able To Detect Analytes,” by Rose, et al.;and U.S. patent application Ser. No. 10/823,093, filed Apr. 12, 2004,entitled “Emissive Sensors and Devices Incorporating These Sensors,” bySwager, et al.; U.S. patent application Ser. No. 10/764,768, filed Jan.26, 2004, entitled “Polymers with High Internal Free Volume,” Swager, etal.

In some embodiments, the polymer is provided in conjunction with amaterial defining a substantially non-light scattering optical mediumwhich can interact optically with the polymer to cause light emission,changes in which can be caused by interaction of the polymer and/or theoptical medium with an analyte. The light emitted may be substantiallymonochromatic, include a limited number of wavelengths (or “modes”), orthe light may be emitted in a broad range of wavelengths. The polymercan be provided in conjunction with the medium by being in opticalcommunication with the medium in some manner, for example, beingpositioned proximate the medium such that light can readily move betweenthe polymer and the medium, or provided directly upon the medium itself.For example, the polymer can be provided as a thin layer on a surface ofthe optical medium, such as a substrate.

The substantially non-light scattering medium can be transparent to(i.e., not substantially scattered by) wave lengths of electromagneticradiation of interest, that is, wavelengths at which emission occurs andcan be changed by the presence of an analyte. The optical medium can bereadily selected by those of ordinary skill in the art based upon thepresent disclosure from materials including silica, other glasses,polymers such as polycarbonate, or the like. In one embodiment, theoptical medium provides optical feedback to the polymer, which acts asan emitter of light, sufficient to create amplified stimulated emission.In this case, the optical medium serves as a medium for the collectionof light at a concentration high enough to provide amplified stimulatedemission. Those of ordinary skill in the art will recognize and readilybe able to select and construct combinations of polymers and opticalmedia of dimension and geometry such that optical characteristicsincluding amplified stimulated emission as described here and can occur.Where the optical medium provides feedback at selective modes, theoptical medium alone and/or in combination with the polymer can define alaser.

A variety of definitions are now provided, which will aid inunderstanding various aspects of the invention. Following, andinterspersed with these definitions, is additional disclosure that willmore fully describe the invention.

The term “fluid,” as used herein, is defined as a substance that tendsto flow and to conform to the outline of its container. Typically,fluids are materials that are unable to withstand a static shear stress.When a shear stress is applied to a fluid, it experiences a continuingand permanent distortion. Typical fluids include liquids and gases.

As used herein, the term “determining” (and similar terms) generallyrefers to the measurement and/or analysis of a species, for example,quantitatively or qualitatively, and/or the detection of the presence orabsence of the species. “Determining” may also refer to the measurementand/or analysis of an interaction between two or more species, forexample, quantitatively or qualitatively, and/or by detecting thepresence or absence of the interaction.

As used herein, the term “sample” refers to any medium that can beevaluated in accordance with the invention, such as air, soil, water, abiological sample, etc. A “sample suspected of containing” a particularcomponent means a sample with respect to which the content of thecomponent is unknown. For example, a soil sample may be suspected ofhaving one or more explosive agents, but is not known to have theexplosive agent. “Sample” in this context includes naturally-occurringsamples, such as soil samples, water samples, air samples, samples fromfood, livestock, plants, etc.

As used herein, “binding” includes covalent binding, ionic binding,hydrogen binding, van der Waals interactions, metal ligand binding,dative binding, coordinated binding, hydrophobic interactions, or thelike.

As used herein, “alkyl” is given its ordinary meaning as used in thefield of organic chemistry. Alkyl (i.e., aliphatic) moieties useful forpracticing the invention can contain any of a wide number of carbonatoms, for example, between and 1 and 25 carbon atoms, between 1 and 20carbon atoms, between 1 and 15 carbon atoms, between 1 and 10 carbonatoms, or between 1 and 5 carbon atoms. In some embodiments, the alkylmoiety will contain at least 1 carbon atom, at least 3 carbon atoms, atleast 5 carbon atoms, or at least 10 carbon atoms; in other embodiments,the alkyl moiety will have at most 10 carbon atoms, at most 5 carbonatoms, or at most 3 carbon atoms. The carbon atoms within the alkylmoiety may be arranged in any configuration within the alkyl moiety, forexample, as a straight chain (i.e., a n-alkyl such as methyl, ethyl,propyl, butyl, pentyl, hexyl, heptyl, octyl, etc.) or a branched chain,i.e., a chain where there is at least one carbon atom that is covalentlybonded to at least three carbon atoms (e.g., a t-butyl moiety, anisoalkyl moiety such as an isopropyl moiety or an isobutyl moiety,etc.). In certain embodiments, a straight chain or branched chain alkylhas about 30 or fewer carbon atoms (e.g., C₁-C₃₀ for straight chain,C₃-C₃₀ for branched chain), in some cases, about 20 or fewer atoms, etc.The alkyl moiety may contain only single bonds (i.e., the alkyl is“saturated”), or may contain one or more double and/or triple bondswithin its structure (i.e., the alkyl is “unsaturated”), for example, asin an alkene, an alkyne, an alkadiene, an alkadiyne, an alkenyne, etc.

In some cases, the alkyl moiety contains only carbon and hydrogen atoms;however, in other embodiments, the alkyl moiety may also contain one ormore substituents, i.e., a non-carbon and non-hydrogen atom (“a“heteroatom”) may be present within the alkyl moiety. Non-limitingexamples of heteroatoms include halogens, boron, nitrogen, oxygen,phosphorus, sulfur, and selenium. For example, the alkyl moiety mayinclude a halogen, an alkoxy moiety (e.g., methoxy or ethoxy), an aminemoiety (e.g., a primary, secondary, or tertiary amine), a carbonyl(e.g., an aldehyde and/or a ketone), and/or a hydroxide as asubstituent. If more than substituent is present within the alkylmoiety, then the substituents may each independently be the same ordifferent. In one embodiment, an alkyl is a perhalogenated alkyl, asfurther discussed below.

An alkyl may be acyclic, or cyclic in some cases. Cyclic alkyls include,but are not limited to, cycloalkyl (alicyclic) moieties, aromaticmoieties, aralkyl moieties, alkyl substituted cycloalkylmoieties,cycloalkyl substituted alkylmoieties, etc. Certain cycloalkyls may havefrom about 3 to about 10 carbon atoms in their ring structure, forinstance, 5, 6, or 7 carbons in a ring structure.

An “aromatic” moiety is given its ordinary meaning as used in the art,i.e., a moiety having at least one ring in which some electrons aredelocalized in the ring. For instance, the aromatic moiety may include abenzene moiety, a naphthalenyl moiety, an anthracenyl moiety, apyridinyl moiety, a furanyl moiety, etc. Examples of aromatic compoundsinclude, but are not limited to, nitroaromatics such as2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT), nitrotoluene,etc. Other non-limiting examples of aromatics that are of biological orenvironmental importance include, but are not limited to, dioxin,dopamine, aniline, benzene, toluene, and phenols.

The term “aryl” is art-recognized, and includes 5-, 6- and 7-memberedsingle-ring aromatic groups that may include from zero to fourheteroatoms, for example, benzene, pyrrole, furan, thiophene, imidazole,oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine, pyridazineand pyrimidine, and the like. Those aryl groups having heteroatoms inthe ring structure may also be referred to as “heteroaryls.” Thearomatic ring may be substituted at one or more ring positions with suchsubstituents as described above, for example, halogen, azide, alkyl,aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro,sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl,silyl, ether, alkylthio, sulfonyl, sulfonamido, ketone, aldehyde, ester,heterocyclyl, aromatic or heteroaromatic moieties, —CF₃, —CN, or thelike. The term “aryl” also includes polycyclic ring systems having twoor more cyclic rings in which two or more carbons are common to twoadjoining rings (the rings are “fused rings”) wherein at least one ofthe rings is aromatic, e.g., the other cyclic rings may be cycloalkyls,cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls. Similarly, theterm “aralkyl” is art-recognized, and includes alkyl groups substitutedwith an aryl group (e.g., an aromatic or heteroaromatic group).

The terms “heterocyclyl” and “heterocyclic group” are art-recognized,and, in some cases, include 3- to 10-membered ring structures, such as3- to 7-membered rings, for example, whose ring structures include oneto four heteroatoms. Heterocycles may also be polycycles in some cases.Heterocyclyl groups include, for example, thiophene, thianthrene, furan,pyran, isobenzofuran, chromene, xanthene, phenoxathiin, pyrrole,imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine,pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine,quinolizine, isoquinoline, quinoline, phthalazine, naphthyridine,quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline,phenanthridine, acridine, pyrimidine, phenanthroline, phenazine,phenarsazine, phenothiazine, furazan, phenoxazine, pyrrolidine, oxolane,thiolane, oxazole, piperidine, piperazine, morpholine, lactones, lactamssuch as azetidinones and pyrrolidinones, sultams, sultones, and thelike. The heterocyclic ring may be substituted at one or more positionswith such substituents as described above, as for example, halogen,alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, amino, nitro,sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl,silyl, ether, alkylthio, sulfonyl, ketone, aldehyde, ester, aheterocyclyl, an aromatic or heteroaromatic moiety, —CF₃, —CN, or thelike.

The definition of each expression, e.g. alkyl, m, n, etc., when itoccurs more than once in any structure, is intended to be independent ofits definition elsewhere in the same structure unless otherwiseindicated expressly or by the context.

A “polymer,” as used herein, is an extended molecular structurecomprising a backbone which optionally contains pendant side groups,where “backbone” generally refers to the longest continuous bond pathwayof the polymer. Those of ordinary skill in the art will be able toidentify the backbone of a polymer. In one embodiment, the polymerincludes one or more polyarylenes, polyarylene vinylenes, polyaryleneethynylenes, and/or ladder polymers, i.e. polymers having a backbonethat can only be severed by breaking two bonds. Examples of suchpolymers include, but are not limited to, polythiophene, polypyrrole,polyacetylene, polyphenylene and substituted derivatives thereof.

Non-limiting examples of polymers suitable for the invention includethose disclosed in U.S. patent application Ser. No. 09/305,379, filedMay 5, 1999, entitled “Emissive Polymers and Devices Incorporating ThesePolymers,” by Swager, et al.; U.S. patent application Ser. No.09/935,060, filed Aug. 21, 2001, entitled “Polymers with High InternalFree Volume,” by Swager, et al.; and U.S. patent application Ser. No.10/680,714, filed Oct. 27, 2003, entitled “Emissive Sensors and DevicesIncorporating These Sensors,” by Swager, et al, each incorporated hereinby reference. Other examples of polymers suitable for the invention aredescribed in more detail herein.

The polymer is, in some cases, a homo-polymer or a co-polymer, such as arandom co-polymer or a block co-polymer. In one embodiment, the polymeris a block co-polymer. An advantageous feature of block co-polymers isthat the effect of a multi-layer can be mimicked. For example, eachblock may have different band gap components, and by nature of thechemical structure of a block co-polymer, each gap component may besegregated in some embodiments. Thus, amplified emissions can beachieved with block co-polymers, and a broad scope of structures can beproduced, according to certain embodiments of the invention. Band gaps,amplifications and selectivities for analytes can thus be achieved bymodification or incorporation of different polymer types. The polymercompositions can vary continuously to give a tapered block structure,according to some embodiments, and the polymers can be synthesized bymethods known to those of ordinary skill in the art, such as stepgrowth, chain growth, or the like.

One aspect of the present invention provides a polymer capable ofemission, wherein the emission may be variable and sensitive to adielectric constant of a surrounding medium. In some cases, the polymeris semiconductive. In one set of embodiments, the polymer has a backboneincluding a plurality of chromophores, which may be interrupted bynon-conjugated groups in some cases. Non-conjugated groups include, forexample, saturated units such as a chain of alkyl groups optionallyinterrupted by heteroatoms. A “chromophore,” as used herein, refers to aspecies that can either absorb or emit electromagnetic radiation. Insome embodiments, the chromophore is capable of absorbing or emittingradiation in the ultraviolet and/or visible range, i.e. absorbing oremitting energy involving excited electronic states. In one embodiment,the chromophore is a conjugated group. As used herein, a “conjugatedgroup” refers to an interconnected chain of at least three atoms, eachatom participating in delocalized pi-bonding.

In another set of embodiments, at least a portion of the polymer isconjugated, i.e. the polymer has one or more conjugated portions. Forexample, in one embodiment, the polymer backbone includes at least oneconjugated group. In the conjugated portion, electron density and/orelectronic charge can be conducted along that portion, and such electrondensity and/or electronic charge may be referred to as being“delocalized.” Within the conjugated portion, each p-orbitalparticipating in the conjugation may have sufficient overlap withadjacent conjugated p-orbitals. In one embodiment, the conjugatedportion is at least about 3 nm in length and in some cases, theconjugated portion is at least about 5 nm, at least about 10 nm, atleast about 15 nm, at least about 25 nm, or more in length. In anotherembodiment, the entire backbone, or substantially all of the entirebackbone, is conjugated and the polymer is referred to as a “conjugatedpolymer,” i.e., the entire polymer, or substantially all of the entirepolymer, is the “conjugated portion.” Polymers having a conjugatedbackbone capable of conducting electronic charge along the backbone aretypically referred to herein as “conducting polymers.” In the presentinvention, the conducting polymers may comprise, in some cases,chromophore monomeric units, or chromophores interspersed between otherconjugated groups. In certain cases, the atoms directly participating inthe conjugation essentially define a plane, which may arise from apreferred arrangement of the p-orbitals to maximize p-orbital overlap,thus maximizing conjugation and electronic conduction. An example of aconjugated-backbone defining essentially a plane of atoms are the carbonatoms of a polyacetylene chain.

In one embodiment, a polymer is provided having a conjugated backbonedefining essentially a plane of atoms. A first group of atoms and asecond group of atoms are attached to the backbone of the polymer. Boththe first and second groups have at least some atoms that are not planarwith the plane of atoms, such that the atoms can be positioned aboveand/or below the conjugated plane of atoms. It is a feature of certainembodiments of the invention that these heights are fixed, where theterm “fixed height” is defined herein as a height of an atom that is notplanar with the plane of atoms, and where the atom is free ofsubstantial rotational motion.

In another embodiment, the present invention relates to a polymercomprising a conjugated backbone and one or more electron donatingand/or electron withdrawing groups associated with the polymer, forexample, bonded to the polymer.

The polymer may comprise, in some cases, one or more electronwithdrawing groups, where a portion of the electron withdrawing group isdirectly bonded to the conjugated backbone, and/or the polymer maycomprise one or more electron withdrawing groups that are not bondeddirectly to the backbone. For example, in some embodiments, the polymercomprises a first moiety where the electron withdrawing group is notbonded directly to the backbone, and a second moiety where the electronwithdrawing group is bonded directly to the conjugated backbone. Theterm “electron-withdrawing group” is art-recognized, and generallyrefers to the tendency of a substituent to attract valence electronsfrom neighboring atoms, i.e., the substituent is electronegative withrespect to neighboring atoms. In some cases, quantification of the levelof electron-withdrawing capability may be given by the Hammett sigma (σ)constant. This constant is described in many references, for instance,March, Advanced Organic Chemistry, 251-59 (McGraw Hill Book Company: NewYork, 1977). The Hammett constant values are generally negative forelectron donating groups (e.g., sigma(P) or σ(P)=−0.66 for NH₂) andpositive for electron withdrawing groups (e.g., sigma(P) or σ(P)=0.78for NO₂). Examples of electron-withdrawing groups include, but are notlimited to, halogenated alkyl groups such as trifluoromethyl, acyl,formyl, sulfonyl, sulfonium, sulfate, nitrile, halide, any electrondeficient ring as compared to benzene (e.g. a benzene ring with anelectron withdrawing group attached to the ring or a nitrogen containingaromatic ring, etc.), or the like. In some embodiments, the electronwithdrawing groups are not bonded directly to the conjugated backbone,and in certain instances, the polymer may have a hyperconjugated 3-Dstructure. Other non-limiting examples of electron withdrawing groupsinclude esters, perhalogenated alkyls, perhalogenated aryls, nitriles,electron deficient heteroaryls, perfluorinated alkyls, or the like.Non-limiting examples of perfluorinated alkyls include perfluorinatedC₁-C₁₂ alkyls; specific examples include —CF₃, —C₂F₅, —C₃F₇, —C₄F₉,—C₅F₁₁, —C₆F₁₃, —C₇F₁₅, —C₈F₁₇, —C₉F₁₉, —C₁₀F₂₁, —C₁₁F₂₃, etc. and allisomers thereof. For example, a polymer may be substituted withfluorinated alcohol groups for hydrogen bonding with weak hydrogenbonded acceptors such as nitro groups. In some cases, electron-poorpolymers, for example, produced through the use of electron withdrawinggroups, can enable quenching by electron-rich analytes and thus, in oneembodiment, sensors having specificity for electron-rich analytes areprovided. Sensitivity to electron-rich analytes can be achieved, in somecases, by substituting a polymer with groups that increase electronaffinity, such as electron withdrawing groups.

Certain perfluorinated alkyls may provide a higher degree of solubilitythan the analogous polymers of equal chain length hydrocarbonsubstituents, according to some embodiments of the invention. In somecases, the perfluorinated alkyls may prevent strong interpolymerinteractions, and in some instances, thin films of these materials maymaintain fluorescence while in the solid state. The high electronaffinity of the perfluorinated alkyls, in some embodiments, maycomplement other sensor materials, e.g., as described herein.

The polymer may be fluorescent and/or semiconductive in some cases. Theterm “fluorescence” is art-recognized and generally refers to theemission of electromagnetic radiation caused by an electronic transitionfrom an excited electronic state of a given spin to a lower energyelectronic state. In yet another embodiment, the present inventionincludes conjugated polymers that produce high fluorescence quantumyields. In some cases, the polymer can also be used to tune electronaffinity. Architectures are provided herein for the covalent attachmentof the conjugated polymers to peptides, nucleic acids, antibodies, etc.,e.g., for biosensor applications that avoid deleterious reductions intheir electronic delocalization. In some cases, conjugated polymershaving three-dimensional structures that display efficient solid-statefluorescence may be used, and hyperconjugation can be used to tuneelectron affinities of the polymers. In one embodiment, multipleconjugated polymers having different electronic properties due tostrongly electron withdrawing groups directly attached to theirbackbones may be used.

Semiconductive polymers having electron withdrawing substituentsdirectly attached to conjugated portions of the polymers are provided inanother embodiment of the invention. For example, semiconductivepolymers containing perfluorinated alkyl groups, or other electronwithdrawing groups, may have a relatively high electron affinity thatprevents oxidative degradation (photobleaching). The term“photobleaching” is art-recognized, and refers to the decrease inabsorbance intensity upon exposure to light and/or, in the case offluorescent materials, a decrease in emission intensity. Theperfluorinated alkyl polymers disclosed herein are generally stableafter one or more hours of irradiation with UV light (e.g. a 450 W,short-arc, Xe lamp) in solid state, under ambient atmosphere.

Polymers having hydrogen-bonding capabilities can also be synthesized,according to other embodiments of the invention. For example, in oneembodiment, the invention provides the ability to detect analytescapable of hydrogen-bonding interactions. In another embodiment, thepolymer is soluble in an organic solvent.

In some embodiments of the invention, the polymers may be present in acomposition that is rigid with respect to the relative orientationbetween the polymers. In one embodiment, the compositions of the presentinvention are rigid to the extent that the polymer arrangement does notsubstantially change over time, upon exposure to solvent or upon heatingto a temperature of no more than about 150° C. That is, the rigidity ofthe side group defining a fixed height may not substantially change andthe height may not be affected upon heating. In one embodiment, theexposure to solvent or heating step occurs over a period of time ofabout 5 minutes, about 10 minutes, about 15 minutes, about 30 minutes,or about 1 hour. In one embodiment, the composition is characterized bya first optical spectrum having at least one maximum or maxima. Thecomposition is then exposed to a solvent or heated to a temperature ofless than about 140° C. and a second optical spectrum is obtained. Amaximum or maxima in the first spectrum differ by no more than about 15nm from a corresponding maximum or maxima in the second spectrum, and insome cases, by no more than about 10 nm or about 5 nm. In anotherembodiment, the maxima in the second spectrum may have an intensitychange of less than about 10%, or about 15% relative to the maxima inthe first spectrum.

In one set of embodiments, the polymer has a structure:

where n is at least 1, A and C are each independently aromatic, and atleast one of B and D comprises a —C═C— structure (i.e., a double bond)or —C≡C— structure (i.e., a triple bond). In another set of embodiments,the polymer has a structure:

where n is at least 1, A is aromatic, and B comprises a —C═C— structure(i.e., a double bond) or —C≡C— structure (i.e., a triple bond).

In some embodiments, the polymer may include one or more pendantaromatic groups. The pendant aromatic groups may increase the opticalcross-section of the polymer, which may enhance absorption efficiencyand/or emission efficiency in some cases. In one set of embodiments, thepolymer has a structure:

where n is at least 1, A and C are each independently aromatic, and Bcomprises a —C═C— structure (i.e., a double bond) or —C≡C— structure(i.e., a triple bond). In another set of embodiments, the polymer has astructure:

where n is at least 1, A, C, and D are each independently aromatic; andB comprises a —C═C— structure (i.e., a double bond) or —C≡C— structure(i.e., a triple bond). In another set of embodiments, the polymer has astructure:

where n is at least 1, A, C, and D are each independently aromatic; Bcomprises a —C═C— structure (i.e., a double bond) or —C≡C— structure(i.e., a triple bond), and each of R¹ and R² independently comprises ahydrocarbon, as further discussed herein. In yet another set ofembodiments, the polymer has a structure:

where n is at least 1, A, C, and D are each independently aromatic, Bcomprises a —C═C— structure (i.e., a double bond) or —C≡C— structure(i.e., a triple bond), and each of R¹, R², R³, and R⁴ independentlycomprises a hydrocarbon. In the above structures, n may be, for example,at least 2, at least 3, at least 5, at least 10, at least 30, at least100, at least 300, at least 1,000, at least 3,000, at least 10,000, atleast 100,000, or at least 1,000,000. In one embodiment, n is less than10⁸.

In some embodiments, the polymer includes one or more hydrocarbon sidechains substantially parallel to the backbone of the polymer, i.e., theside chains may substantially parallel the 3-dimensional structure ofthe backbone (which may or may not be linear). In some cases, one ormore pendant groups may be used to secure the hydrocarbon side chains inan orientation such that they are substantially parallel to the backboneof the polymer. As used herein, a “hydrocarbon” is a moiety comprisingat least carbon and hydrogen, and in some cases, the hydrocarboncomprises heteroatoms such as oxygen, nitrogen, sulfur, etc. In oneembodiment, the hydrocarbon is an alkyl moiety, which may be straight orbranched.

In another set of embodiments, the polymer may be substantiallysurrounded by hydrocarbon. For example, a hydrocarbon may sufficientlysurround the polymer to reduce interaction of the polymer with adjacentpolymer molecules such that the polymers, for instance, so that thepolymer molecules cannot substantially quench each other. As anotherexample, the hydrocarbon may sufficiently surround the polymer such thatthe ability of O₂ or radicals to interact with the polymer is reduced.As yet another example, the hydrocarbon may sufficiently surround thepolymer such that the polymer is not photobleached, i.e., after exposureto light for long periods of time, the polymer does not substantiallylose its lasing abilities.

In another set of embodiments, the polymer has a structure:

where, independently for each occurrence, R is an electron donatingand/or electron withdrawing group or the two instances of R takentogether form an electron deficient ring; B is a double bond, triplebond, or aryl group substituted by one or more R₁; R₁ is R, H, C₁₋₁₂alkyl, C₂₋₁₂ alkenyl, C₂₋₁₂ alkynyl, aryl, aralkyl, heteroaryl, orheteroaralkyl; A is a fused aryl, cycloalkyl, or cycloalkenyl ring; *depicts an end group for the polymer, for example, H, halide, alkyl,alkoxy, and aryl; and n is an integer greater than 1. In some cases, Rmay be an ester, a perhalogenated alkyl group, a perfluorinated alkylgroup (for example, a C₁₋₁₂ perfluorinated alkyl group), —CO₂CH₃,—CO₂C(CH₃)₃. Examples of perfluorinated alkyl group include, but are notlimited to, —CF₃, —C₂F₅, —C₃F₇, —C₄F₉, —C₅F₁₁, —C₆F₁₃, —C₇F₁₅, —C₈F₁₇,—C₉F₁₉, —C₁₀F₂₁, —C₁₁F₂₃, etc. In certain embodiments, at least one setof two R groups taken together form an electron deficient heteroarylmoiety. In some cases, A may be a fused benzene ring. In someembodiments, n is greater than about 10, about 100, about 1,000, about10,000, or about 100,000. In one embodiment, n is less than about 10⁸.As a particular example, R may be —CO₂CH₃ or —CF₃, R₁ may be H, A may bea fused benzene ring, and n may be greater than about 10, 100, 1000,etc.

In yet another set of embodiments, the polymer has a structure:

where, independently for each occurrence, B is a double bond, triplebond, or aryl; R is an electron donating and/or electron withdrawinggroup; R¹ is R, H, C₁₋₆ alkyl, C₂₋₈ alkenyl, C₂₋₈ alkynyl, aryl,aralkyl, heteroaryl, heteroaralkyl, C₁₋₁₂ alkoxy, electron deficientring, or any two adjacent R¹ taken together form a monocyclic, bicyclic,tricyclic, or tetracyclic ring which may be substituted by 1 or moreR; * depicts an end group for the polymer selected from the groupconsisting of H, halide, alkyl, alkoxy or aryl; a is an integer from 1-4inclusive; and m and n are integers 1 or greater. The polymer may be,for example, a random polymer, a block polymer, an alternating polymer,etc. In some cases, R may be an ester, a perhalogenated alkyl group, aperfluorinated alkyl group (for example, a C₁₋₁₂ perfluorinated alkylgroup), —CO₂CH₃, —CO₂C(CH₃)₃. Examples of perfluorinated alkyl groupinclude, but are not limited to, —CF₃, —C₂F₅, —C₃F₇, —C₄F₉, —C₅F₁₁,—C₆F₁₃, —C₇F₁₅, —C₈F₁₇, —C₉F₁₉, —C₁₀F₂₁, —C₁₁F₂₃, etc. In certainembodiments, at least one set of two R groups taken together form anelectron deficient heteroaryl moiety. In some cases, at least one or atleast two of R¹ is a perfluorinated C₁₋₁₂ alkyl or a C₁₋₁₂ alkoxy group.In some cases, a may be 2 or more, and in certain instances, m and n mayindependently be greater than about 10, about 100, about 1,000, about10,000, about 100,000, etc., and in one embodiment, less than about 10⁸.In one embodiment, two sets of adjacent R¹ each form a monocyclic ring,a bicyclic ring, a tricyclic ring, or a tetracyclic ring. In some cases,at least one structure comprises a heteroaryl ring. For example, in oneembodiment, two sets of R¹ each may form a structure:

where * depicts a point of contact with the polymer.

Additional, non-limiting examples of polymers suitable for use in thepresent invention are shown in FIGS. 15A-15G.

In one set of embodiments, the polymer may be present in a film. A filmtypically has a geometry such that one dimension is substantially lessthan the other dimensions (i.e., the “thickness” of the material may besubstantially less than the other dimensions of the material). In somecases, the thickness of the film may affect the sensitivity of thepolymer. For example, the film have a thickness of less than about 1micron, and in some cases, the film may have a thickness of less thanabout 750 nm, less than about 600 nm, less than about 500 nm, less thanabout 400 nm, less than about 200 nm, less than about 100 nm, less thanabout 40 nm, less than about 30 nm, less than about 20 nm, less thanabout 10 nm, less than about 5 nm, or less than about 2 nm. In oneembodiment, the film has a thickness of at least 1 nm.

In one embodiment, the film is attached to a substrate, which may serveas an optical medium in some cases. The film may be attached to thesubstrate using any suitable technique, for example, spin-coatingtechniques. The substrate may have any shape, and include any materialable to support the film. For example, the substrate may besubstantially planar or curved, the substrate may be a rod, a wire, or afiber (for example, a silica fiber), the substrate may comprise discreteparticles (e.g., spherical particles), etc. In some embodiments, e.g.,as shown in FIG. 3, more than one substrate may be present. As anon-limiting example, a glass substrate may be coated with a film ofparylene, then a film of polymer may be coated on the parylene. In FIG.3, FIG. 3A shows a polymer waveguide on a glass substrate, and FIG. 3Bshows a thin polymer layer on parylene. The combined thickness ofpolymer and parylene may act as a waveguide. FIG. 3C shows a thinpolymer layer on a DFB grating, which may significantly reduces thelasing threshold in some cases.

In some cases, the film and the substrate together operate as awaveguide, e.g., as is shown in FIG. 3A. In such cases, the refractiveindex of the film and the refractive index of the substrate may bechosen such that they are nearly or substantially equal. In someinstances, one of the substrate and/or film may be doped in some fashionto match the refractive index of the other. In some cases, one or moreof the substrates may be at least substantially transparent, e.g., tothe excitation and/or emission wavelengths, and/or optically.

In one embodiment, the substrate has the form of a distributed feedbackstructure (“DFB”) or a distributed feedback grating or other structure.As used herein, a “distributed feedback” structure is given its ordinarymeaning in the art, e.g., a structure in which feedback is used to makecertain modes in the resonator oscillate more strongly than others. Thestructure may include a grating (e.g., a Bragg grating) having a spacingchosen to distribute the feedback in both directions, creating acondition that can approach single-mode oscillation, as is shown in FIG.3C. Those of ordinary skill in the art will know of techniques forproducing distributed feedback structures, for example, by usingmicromolding techniques.

Other substrates may be used in other embodiments of the invention. Forexample, in one set of embodiments, the polymer (or film comprising thepolymer) may be attached to or otherwise associated with a non-lightscattering optical medium. Examples of non-light scattering opticalmedium include, but are not limited to, silica, other glasses, polymerssuch as polycarbonate, or the like. In another set of embodiments, thenon-light scattering optical medium includes an optical fiber. Forexample, the polymer may be at least partially coated on a surface ofthe optical fiber (for example, as a film). An interaction of thepolymer with an analyte may cause the polymer to alter an opticalcharacteristic of the optical fiber. For example, if the optical fiberis used as a laser, then the interaction may cause the polymer to altera lasing characteristic of the optical fiber. The non-light scatteringoptical medium, in some embodiments, may carry or “collect” photons,and, through the use of a feedback mechanism (for example, a distributedfeedback structure), may create selective modes for lasing, for examplethrough amplified stimulated emission.

In one aspect, the present invention generally relates to polymers ableto generate amplified stimulated emission of electromagnetic radiation,i.e., a laser, and devices such as sensors able to detect analytes whichincorporate these polymers, e.g., in films. As used herein, a “laser” isgiven its ordinary meaning, i.e., an article able to emit amplified andcoherent electromagnetic radiation having one or more discretefrequencies, typically in response to an electrical or an opticalstimulus (e.g., incident light, or “stimulation” light). The article,when it exhibits such behavior, is said to “lase.” The emitted light mayhave any frequency or wavelength, for example, in the ultraviolet,visible, or infrared wavelengths. Within the laser, atoms may be excitedinto a metastable “excited” energy state (for example, due to electricalor optical stimulation), such that these excited atoms decay to a lowerenergy level, releasing photons. Thus, a coherent beam of radiation maybe produced within the laser. Any suitable lasing mechanism may be usedwithin the invention. In one aspect of the invention, the ability of thepolymer to reach a metastable excited energy state may be affected bythe interaction or association of an analyte with the polymer.

In one set of embodiments, the polymer is able to produce coherent lightunder certain conditions. In some cases, the polymer may exhibit anenhanced lasing characteristic. As used herein, a “lasingcharacteristic” is a characteristic of the polymer that relates to theability of the polymer to enter a metastable excited energy state.Examples of lasing characteristics include, but are not limited to, the“lasing threshold” (i.e., the minimal amount of incident stimulationneeded for the polymer to reach a metastable excited energy state, forexample, the minimal amount of energy, light (photon) intensity, etc.),the stimulated emission (i.e., the amount of energy produced by thepolymer, relative to a fixed standard, such as spontaneous emission),the gain (i.e., the relative amount of energy or photons emitted by thelaser, relative to the amount of incident energy), etc.

In one set of embodiments, interaction of an analyte with the polymermay alter a lasing characteristic of the polymer. For example, lasing ofthe polymer may increase or decrease upon interaction of the polymerwith the analyte. In some cases, interaction of the analyte with thepolymer may change (i.e., increase or decrease) stimulated emission ofthe polymer, relative to spontaneous emission of the polymer, and such achange may be detectable in some fashion, as described herein. In somecases, the relative change between stimulated emission of the polymer,relative to spontaneous emission of the polymer may be at least a factorof 5 times, and in some cases, at least a factor of 10, 20, 30, 40, 50,60, 70, 80, 90, 100, 125, 150, 200, 400, 600, 800, 1,000, or more.

In some embodiments, the laser is an electrically-driven laser. In otherembodiments, the laser may be “optically-driven” to generate amplifiedstimulated emission of radiation. As used herein, “optically-driven”refers to components powered by an external optical or electromagneticradiation source. In an optically-driven device, electromagneticradiation is directed towards a material (such as a polymer) where theatoms are to be excited. The electromagnetic radiation source may be anysuitable source, for example, a flash tube, a diode, or another laser.In yet other embodiments, the laser may include a waveguide or anamplifier.

In one embodiment, the polymer has a quantum yield of at least about50%, at least about 60%, at least about 70%, at least about 75%, atleast about 80%, at least about 85%, at least about 90%, at least about95%, or at least about 97%. As used herein, the “quantum yield” refersto a number of photons emitted per adsorbed photon of a material (suchas a polymer). In some cases, the quantum yield is determined at awavelength of electromagnetic radiation produced by the power source.

In some embodiments, the analyte, upon association with the polymer,introduces a non-radiative pathway in the polymer, which may attenuatelasing. In some cases, an electron transfer event from the excited stateof the polymer to the LUMO of the analyte provides non-radiative decaypathway for the exciton, e.g., as is shown in FIG. 1. Thus, associationof the analyte to the polymer may result in a change in the lasingproperties of the polymer, and such a change may be determinable.

One aspect of the invention provides a sensor comprising one or more ofthe polymers described herein. A “sensor,” as used herein, refers to anydevice or article capable of determining an analyte, i.e., a moleculewhich is to be determined. In one embodiment, the analyte comprises anaromatic moiety. In another embodiment, the analyte is an “explosiveagent,” i.e., an agent able to detonate. Examples of explosive agentsinclude, but are not limited to 2,4,6-trinitrotoluene (TNT) and2,4-dinitrotoluene (DNT), nitroglycerine, gunpowder, etc. Othernon-limiting examples include RDX(hexahydro-1,3,5-trinitro-1,3,5-triaxine), PETN(2,2-bis[(nitrooxy)-methyl]-1,3-propanediol dinitrate (ester)) andnitroaromatics and other nitro-(NO₂) containing species, as furtherdescribed herein. The sensor may determine the absolute value and/or achange in a physical or chemical quantity, such as temperature,pressure, flow rate, or pH, the intensity of light, sound, or radiowaves, the presence of a small molecule, the presence of a biologicalmolecule, a change in a characteristic of a bound molecule, or the like,and convert that determination into a useful input signal for aninformation gathering system. For instance, in one set of embodiments,the polymer exhibits a change in a lasing characteristic uponinteraction of the polymer with an analyte. The interaction between thepolymer and the analyte may be, e.g., through covalent binding, ionicbinding, hydrogen binding, van der Waals interactions, metal ligandbinding, dative binding, coordinated binding, hydrophobic interactions,etc. In one embodiment, the polymer ceases to lase upon interaction ofthe polymer with the analyte. In another embodiment, the polymer beginsto lase upon interaction of the polymer with the analyte. In yet anotherembodiment, the lasing threshold of the polymer may increase or decreaseupon interaction of the polymer with the analyte.

In one set of embodiments, the present invention relates to a sensorcomprising a polymer as described herein, and a detector capable ofdetecting an increase or a decrease in fluorescence. In some cases, thesensor is a biosensor. In certain cases, the polymer and the analyte maybe optically coupled. the term “optically coupled” when used herein withreference to a polymer and an analyte, or other moiety such as areaction entity, refers to an association between any of the analyte,other moiety, and the polymer such that energy can move from one to theother, or in which a change in the association can be detected by achange in a lasing characteristic of the polymer. The coupling betweenthe analyte and the polymer may be direct or indirect (i.e., through alinking agent).

In one set of embodiments, the polymer inherently includes the abilityto determine the analyte. The polymer may be functionalized in somecases, e.g., comprising pendant groups, functional moieties, linkingagents associated with binding partners, etc., to which the analyte maybind and induce a measurable change to the polymer. The binding eventcan be specific or non-specific. The functional moieties may includesimple functional groups, for example, but not limited to, —OH, —CHO,—COON, —SO₃H, —CN, —NH₂, —SH, —COSH, —COOR, a halide, etc.; and/orbiomolecular entities including, but not limited to, amino acids,proteins, sugars, DNA, antibodies, antigens, enzymes, or the like.

In another set of embodiments, the invention provides a polymer and areaction entity with which the analyte interacts, positioned in relationto the polymer such that the analyte can be determined by determining achange in a characteristic of the polymer, for example, a lasingcharacteristic. The term “reaction entity” refers to any entity that caninteract with an analyte in such a manner to cause a detectable changein characteristic of a polymer. For example, the reaction entity mayenhance the interaction between the polymer and the analyte, thereaction entity may generate a new chemical species that has a higheraffinity to the polymer, the reaction entity may enrich the analytearound the polymer, or the like. The reaction entity can comprise abinding partner to which the analyte binds in some cases. The reactionentity, when a binding partner, may also comprise a specific bindingpartner of the analyte. For example, the reaction entity may be anucleic acid, an antibody, a sugar, a carbohydrate, a protein, etc. Areaction entity that is a catalyst can catalyze a reaction involving theanalyte in some instances, resulting in a product that causes adetectable change in a characteristic of the polymer. Another example ofa reaction entity is a reactant that reacts with the analyte, which mayproduce a product that can cause a detectable change in a characteristicof the polymer. The reaction entity can comprise a coating on thepolymer in some embodiments, e.g. a coating of a polymer that recognizesmolecules in, e.g., a gaseous sample, which may cause a change inconductivity of the polymer which, in turn, can cause a detectablechange in a characteristic of the polymer.

The term “binding partner,” as used herein, refers to a molecule thatcan undergo binding with a particular analyte and includes specific,semi-specific, and non-specific binding partners, as known to those ofordinary skill in the art. As used herein the term “specifically binds,”when referring to a binding partner (e.g., protein, nucleic acid,antibody, etc.), refers to a reaction that is determinative of thepresence and/or identity of one or other member of the binding pair in amixture of heterogeneous molecules (e.g., proteins and other biologics).Thus, for example, in the case of a receptor/ligand binding pair, theligand would specifically and/or preferentially select its receptor froma complex mixture of molecules, or vice versa. For example, an enzymewould specifically bind to its substrate, a nucleic acid wouldspecifically bind to its complement, an antibody would specifically bindto its antigen, etc. Other non-limiting examples include nucleic acidsthat specifically bind (hybridize) to their complement, antibodiesspecifically bind to their antigen, or the like. The binding may be byone or more of a variety of mechanisms including, but not limited to,ionic interactions, covalent interactions, hydrophobic interactions, vander Waals interactions, etc.

Thus, in one set of embodiments, the present invention relates to amethod of determining an analyte that is a biological molecule. In oneembodiment, the biological molecule is a protein. In another embodiment,the biological molecule is a peptide. In yet another embodiment, thebiological molecule is a mono- or oligonucleotide. In a furtherembodiment, the biological molecule is RNA. In still another embodiment,the biological molecule is DNA. In another embodiment, the biologicalmolecule is determined when it complexes with another peptide molecule,small molecule, RNA, or DNA.

The reaction entity may be positioned, in some embodiments, relative tothe polymer in such a way as to cause a determinable change in a lasingcharacteristic of the polymer. For instance, the reaction entity may bepositioned within about 100 nanometers of the polymer, within about 50nanometers of the polymer, with n about 10 nanometers of the polymer,etc., and the proximity of the reaction entity to the polymer can bedetermined by those of ordinary skill in the art. In another embodiment,the reaction entity is positioned less than about 5 nanometers from thepolymer. In alternative embodiments, the reaction entity is positionedwithin about 4 nanometers, within about 3 nanometers, within about 2nanometers, or within about 1 nanometer of the polymer. In oneembodiment, the reaction entity is attached to the polymer through alinker. In another embodiment, the polymer itself (or a portion thereof)functions as the reaction entity.

Another set of embodiments of the invention involves an articlecomprising a sample exposure region and a polymer able to detect thepresence or absence of an analyte. The sample exposure region may be anyregion in close proximity to the polymer where a sample in the sampleexposure region addresses at least a portion of the polymer. Examples ofsample exposure regions include, but are not limited to, a well, achannel, a microchannel, a gel, or the like. In some embodiments, thesample exposure region holds a sample proximate the polymer, and/or maydirect a sample toward the polymer for determination of an analyte inthe sample. The polymer may be positioned adjacent to or within thesample exposure region. In other cases, the polymer may be a probe thatis inserted into a fluid or fluid flow path. The polymer probe may alsocomprise a microneedle, and the sample exposure region may beaddressable by a biological sample in certain instances. In thisarrangement, a device that is constructed and arranged for insertion ofa microneedle probe into a biological sample may include a regionsurrounding the microneedle defining the sample exposure region, and asample in the sample exposure region may be addressable by the polymer,and vice versa. Fluid flow channels can be created at a size and scaleadvantageous for use in the invention (microchannels) using a variety oftechniques, such as those described in International Patent PublicationNo. WO 97/33737.

In yet another set of embodiments, an article may comprise a pluralityof polymers as described herein able to detect the presence or absenceof a plurality of one or more analytes. Different polymers may bedifferentially doped in some cases, as described above, thereby varyingthe sensitivity of the polymers to the analyte. Different polymers mayalso be selected based on their ability to interact with specificanalytes in other cases, thereby allowing the determination of a varietyof analytes. The plurality of polymers may be arranged in any suitableconfiguration, for example, randomly oriented, parallel to one another,etc. In one embodiment, the polymers may be oriented in an array on asubstrate.

One aspect of the invention involves a sensing element, which can be asensing element for determining a characteristic of a polymer such as alasing characteristic, for example, where the polymer has determined thepresence, or absence, of an analyte in a sample containing, or suspectedof containing, the analyte. Sensors comprising the polymers of theinvention may be used, for example, in chemical or environmentalapplications to detect explosive agents or other analytes of interest.In some cases, the sample size is less than or equal to about 10microliters, in some cases less than or equal to about 1 microliter, andin some cases less than or equal to about 0.1 microliter. The samplesize may be as small as about 10 nanoliters or less in still othercases.

The sensor also may include, in some cases, a source of energyapplicable to the polymeric composition to cause stimulated radiationemission. The energy can include optical stimulation (e.g., a laser),electromagnetic radiation, electrical energy, chemical energy, etc. Insome instances, the energy is of a frequency that can be absorbed by thepolymer to create a metastable excited energy state, resulting instimulated emission of radiation. The sensor also includes, in somecases, a device for detecting the emission, such as, but not limited to,a photomultiplier, a photodiode or a charge coupled device.

Where a detector is present, any detector capable of determiningcharacteristic, such as a lasing characteristic, associated with thepolymer can be used. The concentration of a species, or analyte, may bedetected using the detector from molar concentrations to micromolarconcentrations, nanomolar concentrations, or less in some instances. Insome cases, sensitivity can be extended to a single molecule. Thus, inone embodiment, an article of the invention is capable of delivering asingle analyte molecule to the polymer, and the detector is constructedand arranged to determine a signal resulting from the interaction of themolecule with the polymer.

In another aspect, the present invention relates to a light emittingdevice (for example, a laser) comprising a polymer as described herein,and a source of electrical current comprising electrodes capable ofsupplying the polymer with electrons. In some embodiments, the polymercomprises perfluorinated alkyls and/or perfluorinated aryls, and incertain cases, at the interface between the electrodes and the polymer,metal-carbon bonds are formed. For example, the polymer may compriseperfluorinated alkyls and/or perfluorinated aryls, and at the interfacebetween the electrode and the polymer, metal-fluoride complexes may beformed. In another example, the polymer comprises a nitrogen-containingelectron-deficient heteroaryl, and at the interface between theelectrode and the polymer, metal-nitrogen bonds are formed. Instillanother example, the polymer comprises a nitrogen-containingelectron-deficient heteroaryl and a perfluorinated alkyl and/or aperfluorinated aryl, and at the interface between the electrode and thepolymer, metal-carbon bonds, metal-nitrogen bonds and/or metal-fluoridebonds may be formed.

The following examples are intended to illustrate certain embodiments ofthe present invention, but do not exemplify the full scope of theinvention.

Example 1

This example demonstrates that attenuation of lasing action in achemically-sensitive, optically-pumped polymer thin film can be asensitive probe for detecting airborne analytes. The change in thelasing response can be over 100-fold more pronounced than theattenuation of the spontaneous emission response, which may increase thedetection sensitivity by a comparable factor. In this example,sensitivity gains were demonstrated in detection of explosive vaporssuch as 2,4,6-trinitrotoluene (“TNT”) and 2,4-dinitrotoluene (“DNT”).Both TNT and DNT introduced non-radiative pathways in the polymer thinfilm, which attenuated lasing. The increased optical losses upon analytedetection resulted in the cessation of the lasing action. Thesensitivity enhancement can be very pronounced for lasing polymer filmspumped at intensities near the lasing threshold. Additionally, thisexample illustrates the development of a TNT-sensitive polymer withrelatively high thin film quantum yields of >85% and relatively highoptical damage thresholds. This example also shows low lasing thresholdsof about 185 nJ/cm² for 30 nm thick polymer films in ambient atmosphere,and about 30 nJ/cm² thresholds for similar films deposited on substratespatterned with distributed feedback gratings. The sensitivity gains viathe lasing mechanism produced enhanced sensitivity for fast detection oftrace analytes such as explosive vapors.

Semiconducting organic polymers are an important class of luminescentsensor materials due to their ability to self-amplify. Their signal gainhas its origins in the facility of these materials to transportexcitons, which allows the short-lived excited states to visit amultitude of potential analyte binding sites. The detection of2,4,6-trinitrotoluene and 2,4-dinitrotoluene using semiconductor polymerthin films enables the detection of buried landmines based on anexplosive vapor signature. DNT is a synthetic byproduct of themanufacture of TNT and is often present in landmines containing TNT. Thevapor pressure of DNT is much higher (about 100 ppb) than TNT (about 5ppb). Thus, in some cases, DNT can be used to detect a buried mine eventhough it is less than 10% of the explosive component of a buriedlandmine. In TNT/DNT detection, the signal, fluorescence quenching isthe result of the interaction between these nitroaromatic compounds (TNTor DNT), an electron-deficient pi-acid, and an electron-richsemiconductive polymer (FIG. 1). This quenching of emission may be theresult of causing the polymer to reach ground state i.e., TNT/DNT chargetransfer complexes may give rise to non-radiative states within the bandgap, and electron-transfer from the organic polymer excited state to abound TNT/DNT state. In some cases, rapid back-electron transfer mayreturn the polymer to its ground state.

In this example, polymer 5 of FIG. 2 was used to demonstrate a lasingamplification scheme in SOPs (“semiconductive organic polymers”).Schematic diagrams of the experimental apparatus used in this exampleare shown in FIGS. 11-13. Polymer 5 is generally photophysical, stabile,and is also sensitive to TNT and DNT, as discussed in this example. Itsthin film luminescence spectrum peaks at λ (lambda)=505 nm and has aradiative lifetime of τ (tau)=650 ps. The rapid radiative relaxationcontributes to its high fluorescence efficiency in spun-cast thin filmsof Φ (Phi)=85%, measured by comparison to a standard of9,10-diphenylanthracence in PMMA (Φ (Phi)=83%). The pendant aromaticrings were designed into this system to increase the opticalcross-section, which may enhance both the absorption and emissionefficiency. The specific substitution pattern of the pendant rings waschosen to bias the orientation of the hydrocarbon side chains parallelto the polymer backbone. The backbone of polymer 5 was effectivelyencapsulated in hydrocarbon, thereby preventing strong interpolymerassociations that typically lower the emission efficiencies.Furthermore, the resistance of polymer 5 to photobleaching can beattributed to this protective sheath of hydrocarbon chains. The extendedpi-orbital interactions in polymer 5 created a band structure that canfacilitate exciton transport. Diffusion lengths of about 100 Å(angstroms) have also been measured.

The lasing action was generated by optically exciting thin films ofpolymer 5 with a 4 ns long nitrogen laser pulses (λ (lambda)=337 nm) atan operating frequency of 30 Hz. The beam was focused into a 9 by 0.9 mmstripe, and emission collected at a 60° angle from the excitation beam,which was incident normal to the substrate. All experiments wereperformed in air.

Simple asymmetric waveguides (FIG. 3A) were formed by spin casting thinfilms of polymer 5 from 50 mg/mL hexane solution onto glass substrates,with film thickness ranging from about 300 Å (angstroms) to about 4000 Å(angstroms). For films thicker than about 500 Å (angstroms), a multimodeamplified stimulated emission (ASE) peaked at λ (lambda)=535 nm,coinciding with the first vibronic transition (0,1) of polymer 5. Theselective emission from this mode may be governed by the reabsorption ofthe (0,0) emission within the thin films.

Given that the exciton diffusion length normal to the film surface canbe estimated to an order of 100 Å (angstroms), for sensitivity in aTNT/DNT sensory device, film thicknesses of the order of about 100 Å(angstroms) may be needed in some cases. Such thin films, however, maynot be able to support waveguided optical modes of the laser structure.TNT/DNT exciton quenching of the surface molecules may be overshadowedby the unattenuated emission of the bulk, which may severely limitsensitivity. As a solution, in this example, glass substrates werecoated with a roughly 2000 Å (angstroms) thick layer of opticallytransparent parylene by chemical vapor deposition and then spin castthin polymer overcoats of polymer 5 (FIG. 3B). Parylene's refractiveindex of n=1.67 generally matched the refractive index of the polymern=1.70, so that two in combination could form a waveguide. In thesestructures, ASE emission was observed for polymer layers as thin as 400Å (angstroms). These films were found to be able to detect DNT, in partdue to DNT's higher vapor pressure and penetration depth.

Comparisons of the emission intensities at 500 nm and 535 nm of aroughly 600 Å (angstroms) thick film of polymer 5 on parylene as afunction of input power revealed the onset of ASE for the 535 nm mode tobe about 80 nW. This corresponded to a threshold energy of about 190nJ/cm². Typical measured thresholds ranged from about 190 nJ/cm² toabout 4100 nJ/cm², depending on film quality and age, and the thresholdswere easily reproducible. At these low input powers, signal attenuationdue to photobleaching exposure was minimized, and for short exposuretimes could be neglected.

Example 2

To further lower the ASE threshold, a distributed feedback (DFB)structure was prepared in this example, as shown in FIG. 3C, with anin-plane periodic reflection matched to the green light of the lasingemission. By facilitation of ASE, the DFB improved device stability bylowering the required optical pumping power, which reduced thephoto-oxidation processes. The optical confinement also reduced the needfor larger optical densities of the active polymer and thereby allowedfor lasing in layers of polymer 5 that were thinner than the excitondiffusion lengths for enhanced sensitivity.

DFB structures were fabricated from PDMS and over-coated with polymer 5applied by conventional spin-coating with a thickness of about 400 Å(angstroms) The lasing threshold was found to be further reduced (FIG.4) as compared to structures lacking a DFB. The resulting thresholdreduction was about a factor of 3 compared to a similar film on glass.

FIG. 4 shows a low lasing threshold of polymer 5 atop a PDMS DFBstructure. In FIG. 4, the emission intensity of stimulated peak (536 nm)was a function of the input power. The lasing threshold wasapproximately at 12 nW with same spot size used on glass and paralenestructures.

To measure the chemosensing response, paralyene/polymer 5 films wereexposed to a static saturated vapor pressure of DNT in air. Two-minuteexposures to saturated DNT vapor significantly decreased both theprimary PL emission as well as the ASE observed at 535 nm from the firstvibronic transition (FIG. 5A). The spontaneous emission peak at 500 nmhad its emission intensity reduced by a factor of about 2. In contrast,the 535 nm peak had its intensity reduced by more than a factor of 10for pumping power of about 230 nW (FIG. 5B). Depending on the power ofthe excitation beam, larger differential between exposed and unexposedsample can be registered.

FIG. 5 shows a spectral response of the optically pumped 750 Å(angstroms) film of polymer 5 on parelene coated glass before and aftera 2 minute exposure to DNT. FIG. 5A shows emission intensity as afunction of pump input power at 500 nm (corresponding to spontaneousemission) and at 535 nm (corresponding to ASE) before and after the DNTexposure. FIG. 5B shows emission spectra before exposure divided byemission spectra after exposure at 95 nW, 135 nW, and 223 nW inputpower. The largest signal was observed at lasing wavelength at highestinput power.

Amplification due to exciton diffusion in SOPs was reduced at highquenching levels where multiple quenchers may be present in thediffusion path of the excitons. Similarly optimal sensitivities to ASEmay arise close to the thresholds where small loses may provide maximalattenuation. To realize the optimal sensitivity to DNT with ASE, shorterDNT exposure times were investigated at a pump power of about 330 nW.When films were exposed to saturated DNT vapor (100 ppb) for 1 s, asignificant attenuation in the ASE peak was observed. No measurableattenuation was concurrently observed in the spontaneous peak (FIG. 6).FIG. 6 shows ASE attenuation in the absence of spontaneous attenuationupon 1 s exposure to saturated DNT vapor pressure.

Example 3

This example illustrates the use of dip-coated fiber optics to show anASE with significantly thinner SOP coating layer. This devicearchitecture may provide a significant response to DNT in some cases.

Samples were prepared by dipping a 25 micron diameter silica fiber intoa methylene chloride solution of polymer 5 (1 mg/mL to 10 mg/mL). A thinpolymer film was deposited upon controlled removal of the fibercladding. The thickness was estimated by dissolving the material afteranalysis and measuring the absorbance of the resulting solution. Thelasing action was generated in the same manner as the previous studiesand the samples were exposed to a saturated vapor pressure of TNT forconstant time increments.

In the coated fiber samples, unambiguous ASE attenuation was observedupon saturated TNT exposure for discreet time intervals while thespontaneous emission of the system remained constant (FIG. 7). FIG. 7shows ASE attenuation in the absence of spontaneous attenuation upon 1.5min exposure to saturated TNT vapor pressure. The lasing thresholds werehigher in the fiber optic configuration due to a thinner active layer,so care was taken to ensure that photobleaching did not contribute tothe observed signal. All spectra were averages of five differentmeasurements to minimize the effect of pulse-to-pulse laser powerfluctuations.

FIG. 9 shows laser power output versus pumping power input for achemosensitive laser before and after analyte (in this case TNT)exposure. The biggest differentiation between the “before TNT” and“after TNT” signal was observed when the laser was initially pumped justabove the threshold.

FIG. 10 shows an ASE threshold increase upon 1.5 min exposure tosaturated TNT vapor pressure at 540 nm.

Example 4

To better understand the impact of the quenching process on lasingaction, this example modeled the laser electronic levels and excitationpopulations. Following the formalism previously proposed for lasing inorganic solids, a four level system was used (FIG. 8), where the levelsrefer to: (1) the electronic and geometric ground state of the molecule,(2) the electronic ground state and the nuclear excited state, (3) theelectronic excited state and nuclear ground state and (4) the electronicand nuclear excited state. The origin of levels 2 and 4 is based on thethan the Franck-Condon principle, which states that electronictransitions occur more quickly than the internuclear distances relay totheir equilibrium geometries. For all organic materials, theFranck-Condon nuclear relaxation is accompanied by a red shift in theelectronic transition energy, known as the Franck-Condon shift, thusjustifying the treatment of these states as separate levels. In SOPs,there is an additional shift, which is further enhanced by the inherentdisorder in the polymer backbone that creates a dispersion of the energylevels. In these materials excitons cascade from the higher energystates to the lower energy levels and thereby increase the Stokes shift.The 4-3 and 2-1 transitions are characterized by the rates 1/τ₄₃ (tau₄₃)and 1/τ₂₁ (tau₂₁) respectively. The transition from level 1 to level 4occurs by optical pumping process, characterized by the rate R. Thetransition from level 3 to 2 occurs by one of four routes: spontaneousradiative relaxation (with rate 1/τ_(sp) (tau_(sp))), stimulatedemission (with rate W), spontaneous non-radiative relaxation (with rate1/τ_(nr)(tau_(nr))), and TNT quenching (with rate 1/τ_(q)(tau_(q))).

In general, the 4-3 and 2-1 transitions are much faster than any of theother transitions in the system, i.e.,

96 ₄₃,τ₂₁<<τ_(sp),τ_(nr),τ_(q),1/W,

and so the pumping process was generally approximated as occurringdirectly into level 3 and the population in level 2 is generally assumedto be negligible. This yielded the following rate equation governing thepopulation in level 3:

${\frac{N_{3}}{t} = {R - {N_{3}W} - \frac{N_{3}}{\tau_{32}}}},$

where

$\frac{1}{\tau_{32}} = {\frac{1}{\tau_{sp}} + \frac{1}{\tau_{nr}} + {\frac{1}{\tau_{q}}.}}$

Since N₂˜0, the population difference, N, is given by N₃. Atequilibrium, the populations were constant, yielding:

$N = {{R( {W + \frac{1}{\tau_{32}}} )}^{- 1}.}$

The population difference in the absence of lasing, N₀, was obtained bysetting W to zero, yielding:

N₀=Rτ₃₂

To achieve lasing, this population difference must increase beyond theso-called threshold population difference, N_(th), which is thepopulation difference at which point the gain due to stimulated emissionequals the optical cavity losses.

The optical cavity losses were evaluated in this system, as the opticalabsorption at the lasing wavelength was negligible (due to the largeFranck-Condon shift). Therefore only mirror losses contributed, andassuming a symmetric cavity, the distributed cavity loss coefficient, a(alpha), was obtained:

${\alpha = {\frac{1}{d}{\ln ( \frac{1}{\Re} )}}},$

where d is the cavity length and

is the minor power reflectivity.

Prior to the onset of lasing, the photon flux present in the cavity atthe lasing mode, φ (phi), is relatively small and so the effect ofstimulated emission on the populations was small. The gain is this case,known as the “small-signal” gain, γ₀ (gamma₀), was given by:

γ₀(ν)=N ₀σ(ν),

where σ(ν) (sigma (nu)) was the stimulated emission transition crosssection. (Note that the stimulated transition rate, W, is related to φ(phi) and σ(ν) (sigma (nu)) by W=φσ(ν).) Using the expression from abovefor N₀:

γ₀(ν)=Rσ(ν)τ₃₂.

The lasing threshold corresponds to the point at which:

α=γ₀(ν),

indicating that:

${{\frac{1}{d}{\ln ( \frac{1}{\Re} )}} = {R\; {\sigma (v)}\tau_{32}}},$

yielding a threshold pump rate, R_(th), of:

$R_{th} = {\frac{1}{{\sigma (v)}d\; \tau_{32}}{{\ln ( \frac{1}{\Re} )}.}}$

From this expression, it can be seen that the introduction of TNTquenching modified the threshold of the laser through τ₃₂ (tau₃₂) alone,since σ(ν) (sigma (nu)), d, and

were all independent of the presence of TNT. Furthermore, since it hasbeen shown that the presence of TNT does not alter the opticalabsorption of the polymer film, the relationship between the incidentpump power and the pumping rate should remain unchanged as well.

Above threshold, the differential quantum efficiency of the laser isnear 100%, meaning that every photon absorbed above threshold goes intothe lasing mode. Therefore:

P_(laser)∝P_(pump)−P_(th),

where P_(th) is simply the pump power required to reach R_(th). Sincethe pumping rate R is linearly proportional to the pump power (relatedby a constant determined by the film absorptivity), the change in P_(th)following the introduction of TNT would be inversely proportional to thechange τ₃₂ (tau₃₂). In particular, the threshold pump power in thepresence of the TNT quenching is given by:

P_(th)′=βP_(th),

and so, for the output power in the presence of the TNT quenching:

P_(laser)′∝P_(pump)−βP_(th),

where

$\beta = {\frac{\tau_{32}}{\tau_{32}^{\prime}}.}$

This allows the sensitivity of the laser to be specified, in terms ofthe fraction change in the output power, f_(power),

${f_{power} = \frac{P_{pump} - {\beta \; P_{th}}}{P_{pump} - P_{th}}},$

assuming that the sensor is operated using a fixed pump power. This iscompared to the case of photoluminescence (PL) quenching, wheref_(power) is simply β⁻¹ (beta⁻¹)

The laser had the advantage that one can design a laser with asensitivity disproportionate to β⁻¹ (beta⁻¹) by operating just abovethreshold. Consider the following example, where the TNT presence yieldsa β (beta) of 2. If the laser is operated at twice the threshold, thenthe presence of the TNT brings the laser output down to zero, yielding aquench of 100%, compared to a PL quench of 50%. Therefore, the closer tothreshold that the laser can be reliably operated the better thesensitivity. This can be seen in FIG. 9 for a hypothetical example andin FIG. 10 for a measured data set.

The influence of TNT exposure on lasing threshold is shown in FIG. 10.The above equations describe the quenching effects of TNT on thepolymer-coated fiber optic. At higher input powers the difference inemission intensity before and after TNT exposure continues to increase.This allows one to gain much more quenching signal by increasing theinput power. In some cases, however, with longer operating times (>1min), the higher power may lead to photobleaching, which may interferewith the quenching response. However, in certain instances wheregreatest amount of signal is required, one may achieve this throughincreasing the input power while shortening operating lifetime of theactive polymer film.

In conclusion, asymmetric waveguide structures were constructed usingthe polymers of the invention. Through optical pumping, ASE was readilyobserved at lower thresholds than any previously reported. Lowthresholds are important in preventing photobleaching and hence, in somecases, devices using these polymers may be operated in ambient air.Significantly amplified responses were measured upon exposure of thepolymer to saturated vapor pressure of DNT and TNT. Responses weremeasured in the lasing peak before any attenuation was observed in thespontaneous peak.

Example 5

This example illustrates a semiconducting polymer having electronwithdrawing groups bonded to a non-conjugated portion of the polymer. Toperturb the electronic structure of the conjugated polymer withoutinterrupting conjugation by adding steric bulk in the plane of polymerbackbone, a [2.2.2] bicyclic ring system containing anelectron-deficient double bond that can interact with the polymerbackbone in a hyperconjugative fashion was designed (FIG. 16A). FIG. 16Aillustrates the synthesis of the [2.2.2] bicyclic ring poly (phenylenevinylene) (“PPV”) compound. In this figure, (a) is NaBH₄, 2-propanol,reflux; (b) is dimethylacetylenedicarboxylate or hexafluoroacetylene,xylene, 140° C.; (c) is NBS, AIBN, CCl₄, reflux; and (d) KO^(t)Bu, THF,r.t.

Compounds 13a and 13b, which each have at least one electron withdrawinggroup appended to the alkene of the bicyclic ring system, weresynthesized and then polymerized by reaction with excess KO^(t)Bu togive polymers 14a and 14b (FIG. 16A). The ester groups in polymer 14aincluded both methyl and (30%) tert-butyl groups, with the latter beingproduced by transesterification under the polymerization conditions. Thetriptycene polymer 14d (FIG. 16B) represented an electron-rich modelpolymer for comparison with relative electron-poor polymers 14a and 14b.The absorption and emission maxima of polymers 14a and 14b were found tobe similar (Table 1). High fluorescence quantum yields were observed forall of the polymers in THF solution and in thin films. The latterfeature was attributed to the reduced interchain interactions enforcedby the three-dimensional frameworks.

TABLE 1 Abs λ_(max) (nm) Em λ_(max) Polymer GPC (Mn) PDI (log ε) (nm) Φτ (ns) 14a (THF) 1.2 × 10⁵ 2.5 401 (3.83) 473, 498 0.58 1.16 14a (Film)401 507 0.42 14b (THF) 6.8 × 10⁴ 2.6 403 (3.48) 471, 497 0.86 0.75 14b(Film) 405 506 0.43 14d (THF) 7.9 × 10⁵ 2.1 413 (4.32) 469, 499 0.760.62 14d (Film) 414 477, 511 0.61

Example 6

This example illustrates various fluorescence quenching studies, usingpolymers similar to those described in Example 5. The effect ofhyperconjugative perturbations on the sensory properties was determinedby investigating fluorescence quenching responses of thin films withexposure to vapors of electron-rich (N,N-dimethyl p-toluidine (DMT)) andelectron-deficient (2,4-dinitrotoluene (DNT)) aromatic compounds. All ofthese thin films displayed the largest quenching response (FIG. 17A) toDNT, despite the fact that it had lower vapor pressure (1.47×10⁻⁴ mmHg)than DMT (1.78×10⁻¹ mmHg). This result may be due to the former's strongpi-acid character that favors association with electron-donatingpi-electron systems. As shown in FIG. 17B, the relative quenchingresponse of polymers 14a, 14b, and 14d reflected the expectedhyperconjugative effects, with polymer 14b being the most oxidizing andpolymer 14d being the most reducing. Hence, polymer 14b gave thestrongest relative response to DMT and the weakest relative response toDNT. Correspondingly, polymer 14d displayed the opposite behavior,having a larger response relative to the other polymers to DNT and aweaker relative response to DMT. Polymer 14a exhibited responsesintermediate to those of polymers 14b and 14d.

To further investigate the quenching behavior, solution Stern-Volmerquenching studies were conducted to determine the rates of static anddynamic quenching by performing steady state and time-resolvedexperiments (FIGS. 17C-17D). Static quenching, involving a preformedcomplex, did not reduce the excited state lifetime whereas dynamicquenching, resulting from diffusion, lowered the lifetime.

The trends in the solution Stern-Volmer rate constants, summarized inTable 2, contrasted markedly to those from the thin film studies. Theelectron-poor polymer 14b exhibited the largest quenching (both staticand dynamic) with DMT (FIGS. 17C-17D). However, polymer 14d, the mostelectron-rich polymer, had a much higher diffusive quenching rate thandiester containing polymer 14a. The deviations from thin film behaviorswere even more pronounced with DNT quenching. In this case, polymer 14dexhibited the lowest static quenching (K_(sv)), even though it has thebest sensitivity in thin films. These results underscore the fact that,in many cases, the sensory behaviors of conjugated polymers in solutioncan be very different than their responses in devices that often employthin films. There are multiple origins for these differences, includingdifferent hydrodynamic volumes for each polymer that can be influencedby the analyte, steric effects that restrict the close approach ofquenchers, and the degree of amplification by energy migration. Forpolymer 14d, its relatively lower solution sensitivity to DNT may be dueto the steric bulk of its alkyl side chains, and as a result it mayexhibit smaller static quenching than polymers 14a and 14b.

TABLE 2 Polymer Quencher K_(D) (M⁻¹) K_(S) (M⁻¹) k_(q) (M⁻¹s⁻¹) 14a DMT0.80 0.92 ± 0.58 6.9 × 10⁸ 14b DMT 5.19 2.49 ± 0.60 7.0 × 10⁹ 14d DMT2.99 0.94 ± 0.67 4.8 × 10⁹ 14a DNT 11.00 86 ± 65 9.4 × 10⁹ 14b DNT 7.60108 ± 93  1.0 × 10¹⁰ 14d DNT 8.00 25 ± 15 1.3 × 10¹⁰

Example 7

This example illustrates the acid-base response of certain PPV polymerswhich may be suitable for use in the present invention. Emerging sensorapplications of certain conjugated polymers may require conjugation tobiorecognition elements. In this example, the stability of polymers 14aand 14b to conditions associated with solid phase peptide synthesis wastested. Conjugated polymers often may exhibit reactivity with strongelectrophiles such as trifluoroacetic acid (“TFA”). However exposure ofpolymer 14b in CH₂Cl₂ (methylene chloride) solutions of TFA or immersionof solids in neat TFA resulted in no apparent reduction/modification ofits emission. Three drops of trifluoroacetic acid was added to 1 cmquartz cuvette containing polymers 14a and 14b dissolved in CH₂Cl₂ atroom temperature, respectively, and their emission spectra wereobserved. In the case of polymer 14a, the fluorescence spectra wererecorded with the increase of concentration of pyridine added to theCH₂Cl₂-TFA suspension of polymer 14a (FIGS. 18A-18B). Methylene chloridesolutions containing polymer 14a were quenched with the addition of TFA;however, its fluorescence appeared to be immediately and completelyrecovered without any spectral shift after neutralization with pyridine.Aqueous acid treatment of polymer 14a lead to the hydrolysis of bothester groups to give polymer 14c. Polymer 14a may also be readilymodified with amide or glycol moieties, which are of interest from thestandpoint of biocompatibility.

Example 8

This example illustrates the synthesis of various semiconducting PPVpolymers having electron withdrawing groups bonded directly to theconjugated backbone. The starting materials used in this example areknown or can be prepared by known processes from commercially availablematerials. The products of the reactions described herein are isolatedby conventional means such as extraction, crystallization, distillation,chromatography, and the like. The synthetic procedure is illustrated inFIGS. 19A-19N, where the electron withdrawing group is a perfluorinatedalkyl.

Example 9

This example demonstrates the stability of certain PPV polymerscomprising perfluorinated alkyls. Semiconductive polymers containingperfluorinated alkyls have a high electron affinity that may preventoxidative degradation (photobleaching). The photobleaching studiesdescribed in this example revealed that the perfluoroalkylsemiconductive polymers had superior stability, when compared to othersemiconductive organic polymers.

For example, photobleaching studies with UV light on trifluoromethylcontaining PPV showed no change with excitation at 320 nm for 2.5 hourswith slit widths of 20 nm (FIGS. 20A-20B). A schematic diagram of thisprocess is shown in FIG. 14. FIG. 20A illustrates a thermogravimetricanalysis of a trifluoromethyl substituted PPV showing no weight loss upto 300° C., and FIG. 20B illustrates the results of a photobleachingstudy of a trifluoromethyl substituted PPV, showing no change withexcitation at 320 nm for 2.5 hours with slit widths of 20 nm.Contrastingly, the same photobleaching experiments performed on alkoxysubstituted PPV (FIG. 20D) showed emissions reduced to 51.2% after just15 min, to 36.3% after 30 min, to 22.5% after 1 hour, to 13.8% after 1.5hours and to 9.8% after 2 hours (FIG. 20C). In these experiments, theexcitation was at 320 nm and the slit width was 20 nm.

These data illustrate that certain semiconductive organic polymers maybe useful in many sensors, photovoltaic, display, and electronictechnologies. The performance of many electronic devices may benefitfrom a reduction of the contact resistance between metal electrodes andpolymers. Other polymers having strongly electron withdrawing groupsused in this application may also display similar stability atinterfaces. In cases where electron-poor nitrogen-containingheterocyclics are present, well-defined and stable metal complexes maybe formed, where nitrogen atoms can be bound to the metal ions.

Example 10

A metal surface and a perfluorinated alkyl polymer may present a morestable interface. This greater stability may be due to the mechanismshown in FIGS. 21A and 21B, and the increased stability may beassociated with sigma bonds between metals and perfluorinated alkyls.This example discusses stable interfaces of PPV comprisingperfluorinated alkyls.

This increased stability may be important for certain OLEDs, also knownas electric luminescence (EL) devices. OLEDs have certain advantages,such as high luminance, self-emission, low driving voltage, nolimitation of view angle, and/or easy fabrication. Therefore, they canbe applicable to planar displays. There are, however, still somedifficulties associated with known OLEDs. These difficulties include,for example, lower efficiency of emission, limited luminance, andlimited durability. An influencing factor for these problems is theefficiency of carrier injection. Since the OLED may be a light emitterhaving two carrier injections where electrons and holes are injectedfrom the cathode and the anode, respectively, into the organic layerssuch that recombination occurs, resulting in the release of energy andthe emission of light, the capability or efficiency of the electrodeinjections may influence the luminance and efficiency of the lightemission. Therefore, it is believed that a more stable interface betweenthe metal electrodes and certain perfluorinated alkyl polymers of thepresent invention may facilitate the charge injection processes and leadto more efficient light-emitting devices.

Example 11

As with the polymers described in the previous examples, where theelectron withdrawing group was bonded to the non-conjugated portion ofthe polymer, similar quenching characteristics may be observed withfluorescent, semiconductive polymers which have the electron withdrawinggroups directly bonded to the conjugated backbone. Quenching can beobserved in the presence of electron donating molecules, such as aminesinstead of electron deficient compounds, such as nitrated aromaticrings.

The materials described in this example may be highly quenched by indoleand potentially tyrosine (see FIG. 21A). Quenching studies measuring theeffect of indole on perfluorinated alkyl substituted PPE shows areduction in fluorescence to 54.5% in 5 seconds, to 36.4% in 1 minute,and to 10.6% in 10 minutes (FIG. 21B). Interestingly, when the same setof experiments was carried out on the same perfluorinated alkylsubstituted PPE, except for the presence of t-butyl groups on thenon-conjugated aryls (FIG. 21C), the reduction in fluorescence was notas great. After 5 seconds, fluorescence reduced to 76.1%, after 1 minuteto 54.3%, and after 10 minutes to 32.6% (FIG. 21D).

This decreased quenching effect indole has on the PPE may be due to thepresence of the electron donating t-butyl groups, which may result in amore electron rich and sterically bulky system. Because the fluorescent,semiconductive polymers discussed above quench in the presence oftyrosine and indole (present in tryptophan), these polymers may beuseful as a general sensor for certain proteins. Similar results may beexpected from the interaction of nucleotide bases with highly electronpoor polymers, thereby representing a detection technology for theseanalytes. The detectible signal would be the reduction in fluorescenceresulting from protein induced quenching. In a broader sense, anyoxidizable material could potentially be detected. The basic materialscan include, for example, nerve agent stimulants, such asdimethyl-methyl-phosphonate (DMMP).

Example 12

This example describes several synthesis techniques useful for preparingvarious polymers potentially suitable for use in the present invention.Following are general methods used in this example. NMR (¹H and ¹³C)spectra were recorded on Varian Mercury 300 MHz or Bruker Avance 400 MHzspectrometers. The chemical shift data for each signal are given inunits of δ (delta) (ppm) relative to tetramethylsilane (TMS) wheredelta(TMS)=0, and referenced to the residual solvent. High-resolutionmass spectra were obtained with a Finnigan MAT 8200 system using sectordouble focus and an electron impact source with an ionizing voltage of70 V. UV-vis spectra were obtained from a Cary 50 UV-VisibleSpectrophotometer. Fluorescence spectra were measured with a SPEXFluorolog-τ3 (tau-3) fluorometer (model FL312, 450W xenon lamp) equippedwith a model 1935B polarization kit. The spectra in solution wereobtained at room temperature using a quartz cuvette with a path lengthof 1 cm. Polymer thin film spectra were recorded by front-face (22.5°detection. Fluorescence quantum yields of polymers in THF solution weredetermined relative equal-absorbing solutions of quinine sulfate (Φ_(F)(phi-F)=0.53 in 0.1 N sulfuric acid). The quantum yields for solid-statethin films were obtained relative to 0.01 mol % 9,10-diphenylanthracenein PMMA (phi-F=0.83) as a reference. The time decay of fluorescence wasdetermined by a phase-modulation method, using frequencies from 10 to300 MHz. The molecular weights of polymers were determined by using aPLgel 5 micron Mixed-C (300×7.5 mm) column and a diode detector at 254nm at a flow rate of 1.0 mL/min in THF. The molecular weights werereported relative to polystyrene standards purchased from Polysciences,Inc. Polymer thin films on a cover glass (18×18 mm) were spin cast on aEC101DT photoresist spinner (Headway Research, Inc.) using a spin rateof 3000 rpm from THF solution. Melting point (m.p.) determination wasperformed using a Laboratory Devices MEL-TEMP instrument (opencapillaries used) and was uncorrected. All solvents were spectral gradeunless otherwise noted. Anhydrous THF, xylene, isopropanol, and carbontetrachloride were purchased from Aldrich Chemical Co., Inc. All othercompounds including analytes (Aldrich) were used as received. All airand water-sensitive synthetic manipulations were performed under anargon atmosphere using standard Schlenk techniques.

1,4-Dimethylanthracene (11). To a solution of 1,4-dimethylanthraquinone(1 g, 4.24 mmol) suspended in 40 mL of isopropanol was added sodiumborohydride (1.6 g, 42.4 mmol) in portions over 1 h at room temperaturewith stirring. The reaction mixture was left to stir at this temperaturefor an additional 30 min before heating to reflux overnight. Thesolution was then cooled to room temperature and quenched by pouringinto 5% HCl solution. The mixture was left to stir for 1 hr and thesolution was filtered to give a yellow solid. The solid was furtherrecrystallized from ethanol to give the product 11 as a bright yellowsolid (0.795 g, 92%): m.p. 70-72° C. (lit. m.p. 74° C.); ¹H NMR (300MHz, CDCl₃): 8.56 (2H, s), 8.06 (2H, dd, J=6.5 and 3.3 Hz), 7.50 (2H,dd, J=6.5 and 3.3 Hz), 7.22 (2H, s), 2.82 (6H, s); HR-MS (EI) calcd. forC₁₆H₁₄ (M+): 206.11, found: 206.11.

9,10-Dihydro-9,10-(1′,2′-dicarbomethoxy)etheno-1,4-dimethyl anthracene(12a). To a solution of 1,4-dimethylanthracene 11 (0.55 g, 2.67 mmol) in10 mL xylene was added dimethylacetylenedicarboxylate (1.90 g, 13.34mmol) at room temperature and stirred at 140° C. for 24 h. The mixturewas allowed to cool to room temperature and the reaction solvent wasremoved under vacuum to give a solid. Further purification byrecrystallization from a mixture of dichloromethane and methanol (1:3)gave the product 12a as a white solid (0.84 g, 90%): m.p. 139-140° C.;¹H NMR (300 MHz, CDCl₃): 7.38 (2H, dd, J=5.4 and 3.0 Hz), 7.03 (2H, dd,J=5.4 and 3.0 Hz), 6.75 (2H, s), 5.72 (2H, s), 3.81 (6H, s), 2.46 (6H,s); ¹³C NMR (75 MHz, CDCl₃): 166.2, 147.3, 144.0, 142.1, 130.1, 126.8,125.6, 124.0, 52.8, 49.6, 18.7; HR-MS (EI) calcd. for C₂₂H₂₀O₄ (M⁺):348.14, found: 348.13.

9,10-Dihydro-9,10-(1′,2′-bis(trifluoromethyl))etheno-1,4-dimethylanthracene (12b). m.p. 155-156° C.; ¹H NMR (300 MHz, CDCl₃): 7.41 (2H,dd, J=5.4 and 3.0 Hz), 7.07 (2H, dd, J=5.4 and 3.0 Hz), 6.79 (2H, s),5.67 (2H, s), 2.44 (6H, s); ¹³C NMR (75 MHz, CDCl₃): 167.3, 143.2,141.3, 130.3, 127.2, 126.1, 124.1, 48.1, 18.3; HR-MS (EI) calcd. forC₂₀H₁₄F₆ (M⁺): 368.0994, found: 368.0995.

1,4-Bis(2-ethylhexyloxy)-5,8-dimethyl-9,10-dihydro-9,10[1′,2′]benzenoanthracene(12d). 1,4-dimethylanthracene (4.10 g, 19.87 mmol) and 1,4-benzoquinone(3.22 g, 29.9 mmol) were refluxed in xylenes for 40 min. Solvent wasremoved in vacuo and the residue were separated by flash chromatography(with polarity ramped from hexanes to 1:1 hexane:dichloromethane). Thefraction containing benzenoanthracene-1,4-dione was separated, dried andredissolved in acetic acid. The solution was heated to reflux and a dropof hydrobromic acid was added. Reflux was continued for 30 min andsolvent was removed under vacuum. The residue was purified bychromatography (1:10 ethyl acetate/dichloromethane) to afford5,8-dimethyl-9,10-dihydro-9,10[1′,2′]benzenoanthracene-1,4-diol (4.9 g,79%): HR-MS (EI) calcd. for C₂₂H₁₈O₂ (M⁺): 314.1307, found: 314.1313.This material was used in subsequent reactions without furthercharacterization.

5,8-Dimethyl-9,10-dihydro-9,10[1′,2′]benzenoanthracene-1,4-diol (8.3 g,26.4 mmol) was dissolved in DMF (30 mL) and sodium hydride (60%suspension in mineral oil, 4.2 g, 0.11 mol) was added in small portions.The reaction mixture was stirred for 30 min under nitrogen and2-ethylhexyl bromide (17.8 g, 0.092 mol) was added. The reaction mixturewas heated for 16 h at 100° C. and the solvent was removed. The residuewas purified by column chromatography (1:10 dichloromethane/hexane) toafford the product 12d as an amorphous solid (9.90 g, 70%). ¹H NMR (300MHz, CDCl₃): 7.42 (2H, m), 7.02 (2H, m), 6.75 (2H, s), 6.50 (2H, s),6.18 (2H, s), 3.87 (2H, s), 3.85 (2H, s), 2.53 (6H, s), 1.86 (2H, m),1.72-1.44 (18H, m), 1.07-0.96 (12H, m); ¹³C NMR (75 MHz, CDCl₃): 148.47,146.09, 144.04, 135.63, 135.59, 129.60, 126.12, 124.92, 123.81, 109.36,109.25, 71.10, 44.12, 40.00, 39.93, 31.22, 31.14, 29.60, 19.45, 24.51,24.48, 23.50, 23.46, 18.61, 18.58, 14.48, 11.74, 11.58; HR-MS (EI)calcd. for C₃₈H₅₀O₂ (M⁺): 538.3811, found: 538.3824.

9,10-Dihydro-9,10-(1′,2′-dicarbomethoxy)etheno-1,4-bis(bromomethyl)anthracene (13a). A mixture of the methyl ester 12a (200 mg, 0.575mmol), N-bromosuccimide (214 mg, 1.2 mmol) and 3 mg AIBN in 5 mL carbontetrachloride was stirred under reflux for 24 h. The mixture was cooledto room temperature and filtered to remove salts. The filtrate waswashed with CCl₄ and the solution was evaporated to give a crudeproduct. This was purified by column chromatography (5:1 hexane/ethylacetate as eluent) to give 13a as a white powder (174 mg, 60%): m.p.168-170° C.; ¹H NMR (300 MHz, CDCl₃): 7.53 (2H, dd, J=5.0 and 3.0 Hz),7.09 (2H, dd, J=5.0 and 3.0 Hz), 6.98 (2H, s), 5.92 (2H, s), 4.75 (2H,d, J=10.2 Hz), 4.55 (2H, d, J=10.2 Hz), 3.84 (6H, s); ¹³C NMR (75 MHz,CDCl₃): 166.0, 147.0, 145.0, 143.0, 133.1, 126.8, 126.3, 124.8, 53.0,49.4, 30.4; HR-MS (EI) calcd. for C₂₂H₁₈O₄Br₂ (M⁺): 503.9566, found:505.9524.

9,10-Dihydro-9,10-(1′,2′-bis(trifluoromethyl))etheno-1,4-bis(bromomethyl)-anthracene(13b). This compound was prepared in a similar procedure as 13a, exceptthat benzene was used as a solvent and benzoyl perodide was used as theinitiator. m.p. 168-170° C.; ¹H NMR (300 MHz, CDCl₃): 7.53 (2H, dd,J=5.1 and 3.0 Hz), 7.12 (2H, dd, J=5.1 and 3.0 Hz), 7.02 (2H, s), 5.87(2H, s), 4.71 (2H, d, J=10.5 Hz), 4.53 (2H, d, J=10.5 Hz); ¹³C NMR (75MHz, CDCl₃): 144.0, 142.2, 133.3, 127.3, 126.6, 124.9, 47.9, 29.6; HR-MS(EI) calcd. for C₂₀H₁₂F₆Br₂ (M⁺): 523.92, found: 523.92.

1,4-Bis(2-ethylhexyloxy)-5,8-bis(bromomethyl)-9,10-dihydro-9,10[1′,2′]benzeno-anthracene(13d). Compound 12d (1.37 g, 2.54 mmol), N-bromosuccimide (0.996 g, 5.60mmol) and benzoyl peroxide (5.0 mg) were refluxed in benzene (100 mL)for 8 h. The solvent was removed and the residue was purified by columnchromatography (1:4 dichloromethane/hexane) to afford the product 13d asan amorphous solid (1.07 g, 61%): ¹H NMR (300 MHz, CDCl₃): 7.48 (2H, m),7.02 (2H, m), 6.92 (2H, s), 6.51 (2H, s), 6.31 (2H, s), 4.84 (2H, m),4.53 (2H, m), 3.88 (4H, s), 1.82 (2H, s), 1.65-1.38 (18H, m), 1.07-0.96(12H, m); ¹³C NMR (75 MHz, CDCl₃): 148.50, 146.54, 144.70, 134.42,134.38, 132.36, 126.00, 125.34, 124.28, 109.88, 109.78, 71.40, 71.37,43.89, 39.97, 39.92, 31.30, 31.28, 30.51, 29.62, 29.50, 24.61, 24.56,23.51, 23.49, 14.52, 14.50, 11.77, 11.66; HR-MS (EI) calcd. forC₃₈H₄₈Br₂O₂: 694.2021, found: 694.2001.

Polymer 14a. Compound 13a (60 mg, 0.12 mmol) was placed in a 25 mLSchlenk flask with a stir bar. The flask was evacuated and back-filledwith argon three times, followed by the addition of dry THF (3 mL).Under an atmosphere of argon, an excess of potassium t-butoxide (1 Msolution in THF, 0.59 mmol) was added to the reaction solution and thiswas left to stir for 2 hours at room temperature. The reaction mixturewas then precipitated into a mixture of methanol and water (10:1).Polymer 14a (30 mg, 73%) was collected by filtration as a yellow-orangesolid: ¹H NMR (300 MHz, CDCl₃): 8.0-7.8 (2H, br), 7.7-7.4 (4H, br),7.2-6.9 (2H, br), 6.4-6.1 (2H, br), 1.6-1.4 (18H, br); M_(n)=123 kDa,PDI=2.5.

Polymer 14b. ¹H NMR (300 MHz, CDCl₃): 7.9-7.6 (6H, br), 7.4-7.3 (2H,br), 6.4-6.2 (2 H, br); M_(n)=684 kDa, PDI=2.5.

Polymer 14d. ¹H NMR (300 MHz, CDCl₃): 7.8-6.5 (m, br, 12H), 3.8 (br,4H), 1.5-0.86 (m, br, 30H); M_(n)=890 kDa, PDI=1.7.

1,4-Bis(trifluoromethyl)-2,5-dibromobenzene (21). Into a 1000 mLround-bottomed flask were placed 250 mL trifluoroacetic acid,1,4-bis(trifluoromethyl)benzene (19 g, 88.7 mmol), and 60 mL sulfuricacid (98%). The mixture was stirred vigorously and NBS (47.4 g, 267mmol) was added in portions at 60° C. over a 5-hour period. Afterstirring at the temperature for 2 d, the mixture was poured into 500 mLof ice-water. The precipitates were filtered and sublimed to give awhite solid (30 g, 91%): m.p. 64-65° C.; ¹H NMR (300 MHz, CDCl₃): 8.01(2H, s); ¹³C NMR (75 MHz, CDCl₃): 134.3, 123.4, 119.7, 119.3; ¹⁹F NMR(282 MHz, CDCl₃): −64.4; HR-MS (EI) calcd. for C₈H₂F₆Br₂ (M⁺): 369.8422,found: 369.8529.

1,4-Bis(trifluoromethyl)-2,5-dibenzoic acid (22). At −75° C., precooledtetrahydrofuran (80 mL) and compound 21 (12.5 g, 33.6 mmol) dissolved inTHF (60 mL) were consecutively added to n-butyllithium (2.5 M solutionin hexane, 30 mL, 75 mmol). A white precipitate formed instantaneously.After 30 min of vigorous stirring at −75° C., the mixture was poured onfreshly crushed dry ice. The reaction mixture was diluted with diethylether (150 mL) and the organic layer was extracted with 2 M NaOH (3×50mL). The acid was collected as a white powder after acidification with 2M HCl of the aqueous phase and recrystallized from hexane to give awhite solid (7 g, 70%): m.p. >230° C.; ¹H NMR (300 MHz, CDCl₃): 8.34(2H, s), 2.06 (2H, s); ¹³C NMR (75 MHz, CDCl₃): 165.1, 134.7, 131.8,129.1, 124.5; ¹⁹F NMR (282 MHz, CDCl₃): −61.5; HR-MS (ESI) calcd. forC₁₆H₁₄ ([M−H]⁻): 300.99, found: 300.99.

1,4-Bis(trifluoromethyl)-2,5-dihydroxymethylbenzene (23). Compound 22(10 g, 33 mmol) was placed into Schlenk flask and followed by theaddition of THF (150 mL). Into the resulting solution was added BH₃-THF(1 M solution in THF, 86.1 mL) dropwise at 0° C. After stirring at roomtemperature for 48 h, a mixture of diethyl ether (100 mL) and water (100mL) was added to the reaction mixture. The organic layer was separated,washed with water (3×50 mL), and dried over MgSO₄. The solid waspurified by column chromatography (5:1 hexane/ethyl acetate as eluent)to afford compound 23 as a white solid (7.1 g, 79%): ¹H NMR (300 MHz,Acetone-d₆): 8.14 (2H, s), 4.87 (4H, s), 2.83 (2H, s); ¹⁹F NMR (282 MHz,Acetone-d₆): −62.1; HR-MS (EI) calcd. for C₁₀H₈F₆O₂ (M⁺): 274.0423,found: 274.0412.

1,4-Bis(trifluoromethyl)-2,5-dibromomethylbenzene (24). At 0° C., PBr₃(10.4 mL, 109 mmol) was slowly added to compound 23 (5 g, 18 mmol)dissolved in THF (125 mL). The reaction mixture was stirred for 30 minat 0° C. and then stirred for 40 h at room temperature. After theaddition of water (20 mL) to quench the reaction under ice-bath, organiclayer was diluted with diethyl ether (100 mL). The organic layer waswashed with water (3×100 mL), dried over anhydrous MgSO₄, evaporated,and sublimed to give compound 24 as a white solid (4.6 g, 65%): m.p.80-81° C.; ¹H NMR (300 MHz, CDCl₃): 7.89 (2H, s), 4.65 (4H, s); ¹³C NMR(75 MHz, CDCl₃): 137.1, 130.8, 124.9, 121.3, 27.1; ¹⁹F NMR (282 MHz,CDCl₃): −61.2; HR-MS (EI) calcd. for C₁₀H₆F₆Br₂ (M⁺): 397.8735, found:397.8744.

1,4-Bis(trifluoromethyl)-2,5-dichloromethylbenzene (25). Tosyl chloride(3.9 g, 20.4 mmol), 4-dimethylaminopyridine (936.3 mg, 7.7 mmol), anddistilled triethylamine (1.73 mL, 12.4 mmol) were added sequentially toa solution of compound 23 in dichloromethane (30 mL) under Ar at roomtemperature. The reaction mixture was stirred at this temperature for 4h. The resulting solution was evaporated and the residue was dilutedwith hexane (100 mL). The organic layer was washed with water (3×50 mL),dried over anhydrous MgSO₄, evaporated, and purified by columnchromatography (hexane as eluent) to give product 25 as a white solid(700 mg, 62%); ¹H NMR (300 MHz, CDCl₃): 7.98 (2H, s), 4.78 (4H, s); ¹⁹FNMR (282 MHz, CDCl₃): −60.6; HR-MS (EI) calcd. for C₁₀H₆F₆Cl₂ (M⁺):309.9745, found: 309.9738.

2,5-Bis(trifluoromethyl)-1,4-xylene-bis(triphenylphosphonium bromide(26). Triphenylphosphine (730 mg, 2.75 mmol) was added to compound 24(500 mg, 1.25 mmol) dissolved in DMF (5 mL) at room temperature. Thereaction mixture was stirred and heated to reflux for 24 h. Aftercooling to room temperature, this solution was poured into 150 mL driedethyl acetate. The precipitate was then filtered, washed with diethylether and dried in vacuo to give a white solid 26 (786 mg, 95%).

Oligomer (27). A solution of sodium ethoxide (30.6 mg, 0.45 mmol)dissolved in abs. ethanol (2 mL) was added dropwise to a solution ofcompound 26 (60 mg, 0.09 mmol) dissolved in chloroform (2 mL) withstirring at room temperature. 2,5-Bis(trifluoromethyl)benzaldehyde (43.9mg, 0.18 mmol) was then added to the reaction mixture. After stirring atroom temperature overnight, the reaction was quenched by the addition ofwater. The solvent was removed in vacuo, the residue was dissolved indichloromethane (30 mL), and the organic layer was washed with water(3×20 mL), dried over MgSO₄, and concentrated in vacuo again. The crudeproduct was purified by column chromatography (hexane as eluent) toafford compound 27 as a white solid (34 mg, 56%): ¹H NMR (300 MHz,CDCl₃): 7.86 (2H, d), 7.63 (2H, d), 7.16 (4H, s), 7.13 (1H, d), 7.09(1H, d), 7.02 (1H, d), 6.99 (1H, d); ¹⁹F NMR (282 MHz, CDCl₃): −61.9,−62.4, −64.5; HR-MS (EI) calcd. for C₂₈H₁₂F₁₈(M⁺): 690.0646, found:690.0670; λ_(max) (abs, CHCl₃)=313 nm, λ_(max) (emi, CHCl₃)=393, 413 nm.

2,5-Bis(perfluorobutyl)-p-xylene (28). A solution of C₄F₉I (0.96 mL, 5.6mmol) was added dropwise over 10 min to a stirred mixture of2,5-diiodo-p-xylene (0.5 g, 1.4 mmol), copper powder (1.4 g, 22.4 mmol)in DMSO (10 mL) at 130° C. The reaction mixture was subsequently stirredfor a further 24 h at this temperature. After cooling to roomtemperature, it was poured into a beaker containing dichloromethane (30mL) and water (30 mL). After filtering, the organic layer was separated,washed with water (3×30 mL), and dried over MgSO₄. The residue waspurified by column chromatography (hexane as eluent) to give the product28 as a white solid (553 mg, 73%).

2,5-Bis(perfluorobutyl)-1,4-dibromomethylbenzene (29). A mixture ofcompound 28 (200 mg, 0.37 mmol), N-bromosuccimide (138 mg, 0.78 mmol),and AIBN (2 mg, 0.01 mmol) in carbon tetrachloride (5 mL) was stirredunder reflux for 24 h. The mixture was cooled to room temperature andfiltered to remove salts. The filtrate was washed with CCl₄ and thesolution was evaporated to give a crude product. This was purified byrecrystallization from hexane to give 29 as a white solid (100 mg, 39%):¹H NMR (300 MHz, CDCl₃): 7.82 (2H, s), 4.62 (4H, s); ¹⁹F NMR (282 MHz,CDCl₃): −81.6, −107.6, −121.9, −125.9; HR-MS (EI) calcd. for C₁₆H₆F₁₈Br₂([M]⁺): 697.85, found ([M]⁺): 697.87.

4-(Perfluorooctyl)-α,α,α-trifluorotoluene (210). A solution of C₈F₁₇I(12 g, 22 mmol) was added dropwise over 10 min to a stirred mixture of4-iodobenzotrifluoride (3 g, 11 mmol), copper powder (5.6 g, 0.088mmol), 2,2′-bipyridine (120 mg, 0.8 mmol), and DMSO (30 mL) at 70° C.The reaction mixture was subsequently stirred for a further 72 h at thistemperature. After cooling to room temperature, it was poured into abeaker containing ether (100 mL) and water (100 mL). After filtering,the organic layer was separated, washed with water (3×50 mL) and driedover MgSO₄. Sublimation gave the product 210 as a white solid (5.6 g,90%): ¹H NMR (300 MHz, CDCl₃): 7.77 (4H, dd, J=8.1 and 8.4 Hz); ¹⁹F NMR(282 MHz, CDCl₃): −64.0, −81.4, −111.6, −121.4, −122.0, −122.1, −122.9,−126.3.

1-Perfluorooctyl-4-trifluoromethyl-2,5-dibromobenzene (211). Into a 500mL round-bottomed flask were placed 120 mL trifluoroacetic acid,compound 210 (12 g, 21.3 mmol), and 36 mL sulfuric acid (98%). Themixture was stirred vigorously and NBS (11.4 g, 63.8 mmol) was added inportions at 60° C. over 5-hour period. After stirring at the temperaturefor 2 d, the mixture was poured into 200 mL of ice-water. Theprecipitates were filtered and sublimed to give a white solid 211 (13.5g, 88%): ¹H NMR (300 MHz, CDCl₃): 8.04 (1H, s), 7.92 (1H, s).

1-Perfluorooctyl-4-trifluoromethyl-2,5-dibenzoic acid (212). At −75° C.,precooled tetrahydrofuran (20 mL) and compound 211 (3 g, 4.16 mmol)dissolved in THF (20 mL) were consecutively added to n-butyllithium (2.5M solution in hexane, 3.66 mL, 9.14 mmol). After stirring at −75° C. for60 min, the mixture was poured into freshly crushed dry ice. Thereaction mixture was diluted with diethyl ether (100 mL) and the organiclayer was extracted with 2 M NaOH (3×30 mL). The acid was collected as awhite powder after acidification with 2 M HCl of the aqueous phase andrecrystallized from hexane to give a white solid 212 (1.65 g, 61%): ¹HNMR (300 MHz, CDCl₃): 8.27 (1H, s), 8.26 (1H, s), 2.07 (2H, s); ¹⁹F NMR(282 MHz, CDCl₃): −61.5, −82.3, −106.2, −119.4, −121.5, −122.6, −123.5,−126.9.

1-Perfluorooctyl-4-trifluoromethyl-2,5-dihydroxymethylbenzene (213).Compound 212 (294 mg, 0.45 mmol) was placed into a Schlenk flask andfollowed by the addition of THF (5 mL). Into the resulting solution wasadded BH₃-THF (1 M solution in THF, 1.17 mL) dropwise at 0° C. Afterstirring at room temperature for 48 h, a mixture of diethyl ether (10mL) and water (10 mL) was added to the reaction mixture. The organiclayer was separated, washed with water (3×10 mL) and dried over MgSO₄.The solid was purified by column chromatography (5:1 hexane/ethylacetate as eluant) to afford compound 213 as a white solid (284 mg,51%): ¹H NMR (300 MHz, Acetone-d₆): 8.26 (1H, s), 8.26 (1H, s), 4.92(2H, s), 4.90 (2H, s), 2.86 (2H, s); ¹⁹F NMR (282 MHz, Acetone-d₆):−62.6, −82.3, −106.7, −121.5, −122.2, 122.6, −123.5, −126.9.

1-Perfluorooctyl-4-trifluoromethyl-2,5-dibromomethylbenzene (214). At 0°C., PBr₃ (0.24 mL, 2.54 mmol) was slowly added to compound 213 (317 mg,0.51 mmol) dissolved in THF (10 mL). The reaction mixture was stirredfor 30 min at 0° C. and then stirred for 40 h at room temperature. Afterthe addition of water (2 mL) to quench the reaction under ice-bath,organic layer was diluted with diethyl ether (20 mL). The organic layerwas washed with water (3×10 mL), dried with anhydrous MgSO₄, evaporated,and sublimed to give compound 214 as a white solid (240 mg, 63%): ¹H NMR(300 MHz, CDCl₃): 7.90 (1H, s), 7.79 (1H, s), 4.64 (2H, s), 4.62 (2H,s); ¹⁹F NMR (282 MHz, CDCl₃): −61.3, −81.3, −107.1, −120.8, −121.5,122.0, −122.9 −126.3; HR-MS (ESI) calcd. for C₁₇H₆F₂₀Br₂ ([M−H]⁻):746.8433, found ([M−HBr+CH₃]⁻: 682.92.

2-(Perfluorodecyl)-p-xylene (215). A solution of C₁₀F₂₁I (4.2 g, 6.5mmol) was added dropwise over 10 min to a stirred mixture of2-bromo-p-xylene (1 g, 5.4 mmol), copper powder (1.9 g, 29.7 mmol), andDMSO (80 mL) at 130° C. The reaction mixture was subsequently stirredfor a further 2 d at this temperature. After cooling to roomtemperature, it was poured into a beaker containing dichloromethane (50mL) and saturated potassium iodide solution (50 mL). After filtering,the organic layer was separated, washed with water (3×30 mL), and driedover MgSO₄. Recrystallization from hexane gave the product 215 as awhite solid (2.7 g, 82%): ¹H NMR (300 MHz, CDCl₃): 7.31 (1H, s), 7.24(1H, d, J=8.1 Hz)), 7.17 (1H, d, J=8.1 Hz)), 2.46 (3H, t, J=3.0 Hz)),2.39 (3H, s); ¹⁹F NMR (282 MHz, CDCl₃): −81.4, −106.7, −121.1, −121.8,−122.0, −122.9, −126.3; HR-MS (EI) calcd. for C₁₈H₉F₂₁ (M⁺): 624.0363,found: 624.0353.

2-(Perfluorodecyl)-1,4-dibromomethylbenzene (216). A mixture of compound215 (648 mg, 1.04 mmol), N-bromosuccimide (406 mg, 2.28 mmol), and AIBN(5.1 mg, 0.03 mmol) in carbon tetrachloride (15 mL) was stirred underreflux for 24 h. The mixture was cooled to room temperature and filteredto remove salts. The filtrate was washed with CCl₄ and the solution wasevaporated to give a crude product. This was purified byrecrystallization from hexane to give 216 as a white powder (550 mg,68%): ¹H NMR (300 MHz, CDCl₃): ¹⁹F NMR (282 MHz, CDCl₃): −81.3, −106.5,−120.8, −121.5, −121.9, −122.9, −126.3; HR-MS (EI) calcd. forC₁₈H₇F₂₁Br₂ ([M−H]⁺): 778.8495, found ([M−H]⁺): 778.8518.

Poly-[2,5-bis(trifluoromethyl)-p-phenylene vinylene] (31a). Compound 24(360 mg, 0.9 mmol) was placed in a 50 mL Schlenk flask with a stir bar.The flask was evacuated and back-filled with argon three times, followedby the addition of dry THF (15 mL). Under an atmosphere of argon, anexcess of potassium t-butoxide (1 M solution in THF, 2.7 mL) was addedto the reaction mixture and this was left to stir for 24 h at roomtemperature. The resulting solution was then poured into a mixture ofmethanol and water (10:1, 250 mL). The polymer (150 mg, 71%) wascollected by filtration as a sparingly soluble yellow-orange solid: ¹HNMR (300 MHz, THF-d₆): 8.5-8.3 (1H, br), 8.0-7.8 (1H, br), 5.7-5.5 (2H,br); M_(n)=13 kDa, PDI=1.9; λ_(max)(abs, THF)=374 nm, λ_(max)(emi,THF)=489, 519 nm.

Poly-[2,5-bis(perfluorobutyl)-p-phenylene vinylene] (31b). M_(n)=5,005,PDI=1.04; λ_(max)(abs, THF)=320 nm, λ_(max)(emi, THF)=440 nm.

Poly-[1-perfluorooctyl-4-trifluoromethyl-p-phenylene vinylene] (31c).M_(n)=3,040, PDI=1.16; λ_(max)(abs, THF)=354 nm, λ_(max)(emi, THF)=470,496 nm.

Poly-[2-(perfluorodecyl)-p-phenylene vinylene] (31d). M_(n)=1,800,PDI=1.40; λ_(max)(abs, DMF)=378 nm, λ_(max)(emi, DMF)=488 nm.

1,1′-[2,5-Bis(trifluoromethyl)-1,4-phenylene-bis(methylene)]-bis[tetrahydrothiophenium]dibromide(217a). Tetrahydrothiophene (0.27 mL, 3 mmol) was added to a suspensionof compound 24 (200 mg, 0.5 mmol) in dry methanol (5 mL). The solid wasdissolved to form a clear solution within 10 min. This solution wasfiltered via 0.45 μm membrane filter and then heated to 50° C. withstirring for 24 h. After cooling down to room temperature, the solventwas completely removed in vacuo and cold acetone (10 mL) was added tothe residue. The precipitate was then filtered and dried to givecompound 217a as a colorless, hygroscopic solid (192 mg, 67%): ¹H NMR(300 MHz, D₂O): 8.17 (2H, s), 4.76 (4H, s), 3.52-3.62 (8H, m), 2.34-2.47(8H, m); ¹⁹F NMR (282 MHz, D₂O): −60.2; HR-MS (EI) calcd. forC₁₈H₂₂F₆S₂Br₂ (M⁺): 573.94, found ([M−Br]⁺): 495.04.

Poly[2,5-bis(trifluoromethyl)-1,4-phenylene vinylene] (218a). To adeoxygenated solution of compound 217a (267 mg, 0.46 mmol) in a mixtureof water (2 mL) and methanol (1 mL) cooled in an ice bath was addeddropwise an ice-cold aqueous sodium hydroxide solution (1 M, 0.46 mL)over 10 min. The reaction mixture was stirred at 0° C. for 8 h under Arand then neutralized with 0.5 M HCl (0.5 mL). The solution was thendialyzed against water over 3 days (3×500 mL), after which the solventwas completely removed.

Polymer 31a. Thin films of polymer 31a were obtained by spin-coating theprecursor polymer solution comprising 218a by thermal conversion at 200°C. and 10⁻⁶ mbar for 5 h: λ_(max)(emi)=485, 513 nm.

1,4-Bis(trifluoromethyl)-2,5-diiodobenzene (219). To a solution of 30 mLH₂SO₄ was added periodic acid (3.18 g, 14 mmol) and potassium iodide(6.90 g, 42 mmol) under an ice bath, and then1,4-bis(trifluoromethyl)benzene (2.17 mL, 14 mmol) was added. Thereaction mixture was then stirred at 70° C. for 5 h. After cooling downto room temperature, the resulting solution was poured into ice waterand then extracted with diethyl ether (100 mL) and 10% sodiumthiosulfate (50 mL). The organic layer was washed with 10% sodiumthiosulfate (3×50 mL), dried over MgSO₄, filtered, and concentrated. Theresidue was recrystallized from hexane to give 219 as a white solid(4.24 g, 65%): ¹H NMR (300 MHz, CDCl₃): δ 8.20 (s, 2H); ¹⁹F NMR (282MHz, CDCl₃): −64.2; HR-MS (EI) calcd. for C₈H₂F₆I₂ (M⁺): 465.81, found:465.8387.

Poly[2,5-bis(trifluoromethyl)-p-phenylene vinylene] (31a). A mixture ofcompound 219 (30 mg, 0.06 mmol), bis(tributylstannyl)ethylene (36.4 mg,0.06 mmol), tri(t-butylphosphine) (0.73 mg, 0.004 mmol),tri(dibenzylideneacetone)dipalladium (0.82 mg, 0.001 mmol), and LiCl(5.1 mg, 0.12 mmol) dissolved in NMP was stirred at 80-100° C. for 48 h.The reaction mixture was cooled to room temperature and then extractedwith chloroform and water. The organic layer was evaporated and thecollected precipitate was washed with methanol to give sparingly solublepolymer 31a. GPC data was obtained from soluble portion in THF:M_(n)=2,650, PDI=1.05. λ_(max)(abs, CHCl₃)=339 nm, λ_(max)(emi,CHCl₃)=406, 423 nm.

2,5-Bis(trifluoromethyl)-1,4-benzenedicarboxyaldehyde (220). At −75° C.,precooled tetrahydrofuran (10 mL) and compound 21 (2 g, 5.4 mmol)dissolved in THF (10 mL) were consecutively added to n-butyllithium (1.6M solution in hexane, 7.4 mL, 11.8 mmol). A white precipitate formedinstantaneously. After 30 min of vigorous stirring at −75° C.,N,N-dimethylformaldehyde (3 mL, 38.8 mmol) was slowly added to thereaction mixture and then stirred for 1 h at −40° C. The dialdehyde wasisolated after neutralization with 2 M HCl, ethereal extraction, andrecrystallization from hexane to give a white solid 220 (539 mg, 37%):¹H NMR (300 MHz, CDCl₃): δ 10.47 (s, 2H), 8.55 (s, 2H); HR-MS (EI)calcd. for C₁₀H₄F₆O₂ (M⁺): 270.01, found: 270.01.

2-Methoxy-5-(2′-ethylhexyloxy)-1,4-xylene-bis(triphenylphosphoniumbromide (222). Triphenylphosphine (1.38 g, 5.24 mmol) was added to1,4-bis(bromomethyl)-2((2-ethylhexyl)oxy)-5-methoxybenzene 221 (1 g,2.38 mmol) dissolved in DMF (10 mL) at room temperature. The reactionmixture was stirred and heated to reflux for 24 h. After cooling to roomtemperature, this solution was poured into 300 mL dried ethyl acetate.The precipitate was then filtered, washed with diethyl ether and driedin vacuo to give a white solid 222 (1.4 g, 93%).

Poly-[(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-alt-2,5-bis(trifluoro methyl)-1,4-phenylene vinylene] (32a).Into a mixture of compound 220 (10 mg, 0.037 mmol) and 222 (24.6 mg,0.037 mmol) dissolved in chloroform (1.5 mL) was added sodium ethoxide(12.6 mg, 0.19 mmol) dissolved in ethanol (1.5 mL). The reaction mixturewas stirred at room temperature overnight. The reaction was quenchedwith 2% HCl solution and the solution was poured into 100 mL of methanolto give orange polymer. Polymer 32a was isolated by filteration, dried,and reprecipitated in methanol: ¹H NMR (300 MHz, CDCl₃): 8.05-7.75 (2H,br), 7.55-7.20 (2H, br), 6.96-6.55 (4H, br), 3.85-3.65 (3H, br),1.45-0.45 (17H, br); M_(n)=5,522, PDI=1.32; λ_(max)(abs, THF)=483 nm,λ_(max)(emi, THF)=531,564 nm.

1,4-Xylene-bis(diethyl)phosphonate (224). A mixture ofbis(halomethyl)benzene 223 (1 g, 3.79 mmol) and triethylphosphite (1.64g, 9.85 mmol) was heated to 130° C. for 1 to 1.5 h with distillationset-up to collect ethyl halide in situ. The temperature was increased to160° C. under reduced pressure to distill the excess phosphite. Themixture was allowed to cool to room temperature and the product waspurified by recrystallization from ether as a white solid (700 mg,48.9%).

2-Perfluorooctyl-5-trifluoromethyl-1,4-xylene-bis(diethyl)phosphonate(225). The synthetic procedure of compound 225 generally followed thatof compound 224.

Polymer 32b. A mixture of compound 220 (10 mg, 0.037 mmol) and 224(13.99 mg, 0.037 mmol) in toluene was stirred and heated to 110° C.under Ar. A solution of potassium tert-butoxide (1 M solution in THF,0.15 mL) was added all at once into hot mixture resulting in colorchange. The mixture was heated to reflux for 17 h, and then cooled downto room temperature. The resulting solution was diluted with toluene (10mL) and 10% acetic acid (5 mL) was added. Organic layer was separatedand washed with water until neutral. Water was removed from organiclayer by Dean-Stark distillation to give insoluble orange solid (polymer32b).

Polymer 32c. M_(n)=3,138, PDI=1.23; λ_(max)(abs, THF)=508 nm,λ_(max)(emi, THF)=549, 594 nm.

Polymer 33a. A solution of potassium tert-butoxide (1 M solution in THF,0.45 mL) was added dropwise to a mixture of compound 24 (21 mg, 0.05mmol) and compound 221 (20 mg, 0.05 mmol) in tetrahydrofuran (“TFT”)(4.5 mL) at room temperature. After stirring at the temperature for 24h, the resulting mixture was poured into methanol (125 mL). Theprecipitate was filtered out and reprecipitated fromtetrahydrofuran/methanol to afford polymer 33a: ¹H NMR (300 MHz, CDCl₃):8.05-7.75 (2H, br); M_(n)=19 kDa, PDI=2.14; λ_(max)(abs, CHCl₃)=488 nm,λ_(max)(emi, CHCl₃)=548 nm.

Polymer 33b. M_(n)=20 kDa, PDI=8.98; λ_(max)(abs, THF)=331, 485 nm,λ_(max)(emi, THF)=440, 564 nm.

Polymer 33c. M_(n)=28 kDa, PDI=2.70; λ_(max)(abs, THF)=508 nm,λ_(max)(emi, THF)=549, 594 nm.

Polymer 33d. M_(n)=8,368, PDI=2.22; λ_(max)(abs, THF)=329 nm,λ_(max)(emi, THF)=483, 508 nm.

Polymer 33e. λ_(max)(abs, THF)=342 nm, λ_(max)(emi, THF)=449 nm.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, kit, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,kits, and/or methods, if such features, systems, articles, materials,kits, and/or methods are not mutually inconsistent, is included withinthe scope of the present invention.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of or “exactly one of,” or, when used inthe claims, “consisting of,” will refer to the inclusion of exactly oneelement of a number or list of elements. In general, the term “or” asused herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of”, when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

1. A device for detecting an analyte, comprising: a polymer that, uponinteraction with an analyte, exhibits a change in a lasingcharacteristic, in combination with an energy source able to cause thepolymer to lase. 2-3. (canceled)
 4. The device of claim 1, wherein theanalyte is able to directly interact with the polymer.
 5. (canceled) 6.The device of claim 1, wherein the analyte is explosive. 7-9. (canceled)10. The device of claim 1, wherein the lasing characteristic is gain.11-12. (canceled)
 13. The device of claim 1, wherein the lasingcharacteristic is a lasing threshold.
 14. The device of claim 13,wherein the lasing threshold increases upon interaction of the polymerwith the analyte. 15-29. (canceled)
 30. The device of claim 1, whereinat least a portion of the polymer is conjugated. 31-43. (canceled) 44.The device of claim 1, wherein the polymer comprises a structure:

wherein n is at least 1, A and C are each aromatic, and at least one ofB and D comprises a double bond or a triple bond.
 45. The device ofclaim 1, wherein the polymer comprises a structure:

wherein n is at least 1, A is aromatic, and B comprises a double bond ora triple bond.
 46. (canceled)
 47. The device of claim 1, wherein thepolymer comprises a structure:

wherein n is at least 1; A, C and D are each aromatic; and B comprises adouble bond or a triple bond.
 48. (canceled)
 49. The device of claim 1,wherein the polymer comprises a structure:

wherein n is at least 1; A, C and D are each aromatic; B comprises adouble bond or a triple bond; and each of R¹, R², R³, and R⁴independently comprises a hydrocarbon.
 50. The device of claim 1,wherein the polymer has a quantum yield of at least about 50% at awavelength of electromagnetic radiation produced by the energy source.51-57. (canceled)
 58. The device of claim 1, further comprising adetector constructed and arranged to determine a change in the lasingcharacteristic of the polymer. 59-61. (canceled)
 62. The device of claim1, wherein the polymer can be exposed to air without substantiallyaltering the lasing characteristic. 63-79. (canceled)
 80. The device ofclaim 1, wherein the article comprises a film comprising the polymer,the film having a thickness of less than about 1 micron, the film beingpresent on a substrate, the substrate and the polymer each having arefractive index, wherein the refractive index of the substrate issubstantially equal to the refractive index of the polymer. 81-82.(canceled)
 83. The device of claim 1, wherein the article comprises afilm comprising the polymer, the film having a thickness of less thanabout 1 micron, the film being present on a substrate, wherein thesubstrate comprises a distributed feedback structure. 84-104. (canceled)105. An article, comprising: a polymer, that, upon interaction with ananalyte, exhibits a change in a stimulated emission signal that is atleast 10 times greater than a change in a spontaneous emission signal ofthe polymer. 106-162. (canceled)
 163. An article, comprising: a polymerthat, upon interaction with an analyte, exhibits a change in a lasingcharacteristic, the polymer further comprising a binding site for ananalyte which, when it binds at the site, changes the lasingcharacteristic. 164-188. (canceled)